First Financial Bankshares (FFIN) 10-Q 2 Aug 21 2021 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2021	Aug. 02, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Quarterly Report	true
Document Transition Report	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Document Period End Date	Jun. 30, 2021
Entity Registrant Name	FIRST FINANCIAL BANKSHARES, INC.
Entity Central Index Key	0000036029
Entity Filer Category	Large Accelerated Filer
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity File Number	0-7674
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	75-0944023
Entity Address, Address Line One	400 Pine Street
Entity Address, City or Town	Abilene
Entity Address, State or Province	TX
City Area Code	325
Local Phone Number	627-7155
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Stock
Trading Symbol	FFIN
Security Exchange Name	NASDAQ
Entity Address, Postal Zip Code	79601
Entity Common Stock, Shares Outstanding		142,359,774

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
ASSETS
CASH AND DUE FROM BANKS	$ 190,061	$ 211,113	$ 188,373
INTEREST-BEARING DEMAND DEPOSITS IN BANKS	654,531	517,971	196,426
Total cash and cash equivalents	844,592	729,084	384,799
SECURITIES AVAILABLE-FOR-SALE, at fair value (amortized cost of these securities was $5,405,189, $3,927,254 and $4,177,179 as of June 30, 2021 and 2020 and December 31, 2020, respectively)	5,578,048	4,393,029	4,118,863
LOANS:
Held-for-investment, excluding PPP loans	4,984,210	4,687,370	4,549,950
PPP loans	320,392	483,663	703,117
Total loans held-for-investments	5,304,602	5,171,033	5,253,067
Less—allowance for credit losses	(62,138)	(66,534)	(68,947)
Net loans held for investment	5,242,464	5,104,499	5,184,120
Held-for-sale ($56,257, $63,293 and $79,585 at fair value at June 30, 2021 and 2020 and December 31, 2020, respectively)	61,802	83,969	66,370
BANK PREMISES AND EQUIPMENT, net	147,655	142,269	138,933
INTANGIBLE ASSETS, net	317,568	318,392	319,365
OTHER ASSETS	136,954	133,258	127,367
Total assets	12,329,083	10,904,500	10,339,817
LIABILITIES AND SHAREHOLDERS' EQUITY
NONINTEREST-BEARING DEPOSITS	3,427,038	2,982,697	2,941,679
INTEREST-BEARING DEPOSITS	6,354,656	5,693,120	5,215,963
Total deposits	9,781,694	8,675,817	8,157,642
DIVIDENDS PAYABLE	21,357	18,484	18,462
BORROWINGS	549,969	430,093	449,224
TRADE DATE PAYABLE	189,838	14,641	33,553
OTHER LIABILITIES	65,856	87,275	98,487
Total liabilities	10,608,714	9,226,310	8,757,368
COMMITMENTS AND CONTINGENCIES
SHAREHOLDERS' EQUITY:
Common stock—($0.01 par value, authorized 200,000,000 shares; 142,359,774, 142,035,396 and 142,161,834 shares issued at June 30, 2021 and 2020 and December 31, 2020, respectively)	1,424	1,422	1,420
Capital surplus	672,288	669,644	666,963
Retained earnings	910,171	836,729	762,830
Treasury stock (shares at cost: 938,629, 932,018 and 938,591 at June 30, 2021 and 2020 and December 31, 2020, respectively)	(9,641)	(9,126)	(8,697)
Deferred Compensation	9,641	9,126	8,697
Accumulated other comprehensive earnings, net	136,486	170,395	151,236
Total shareholders' equity	1,720,369	1,678,190	1,582,449
Total liabilities and shareholders' equity	$ 12,329,083	$ 10,904,500	$ 10,339,817

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Statement of Financial Position [Abstract]
Securities, Available-for-sale, Amortized Cost	$ 5,405,189	$ 4,177,179	$ 3,927,254
Loans held-for-sale, fair value	$ 56,257	$ 79,585	$ 63,293
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000	200,000,000
Common stock, shares issued	142,359,774	142,161,834	142,035,396
Treasury stock, shares	938,629	938,591	932,018

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
INTEREST INCOME:
Interest and fees on loans	$ 66,879	$ 65,932	$ 133,314	$ 128,927
Interest on investment securities:
Taxable	11,449	14,029	21,712	28,684
Exempt from federal income tax	14,060	12,149	27,809	21,844
Interest on federal funds sold and interest-bearing demand deposits in banks	214	87	377	842
Total interest income	92,602	92,197	183,212	180,297
INTEREST EXPENSE:
Interest on deposits	1,560	2,550	3,255	9,230
Other	93	412	184	929
Total interest expense	1,653	2,962	3,439	10,159
Net interest income	90,949	89,235	179,773	170,138
PROVISION FOR CREDIT LOSSES	(1,206)	8,700	(3,203)	18,550
Net interest income after provisions for credit losses	92,155	80,535	182,976	151,588
NONINTEREST INCOME:
Trust fees	8,692	6,961	16,991	14,398
Service charges on deposit accounts	4,928	4,318	9,721	10,233
ATM, interchange and credit card fees	9,853	8,049	18,530	15,449
Gain on sale and fees on mortgage loans	8,291	13,676	18,185	17,528
Net gain on sale of available-for-sale securities	5	1,512	813	3,574
Net gain on sale of foreclosed assets	1	52	56	53
Net gain (loss) on sale of assets	74	(24)	219	92
Interest on loan recoveries	704	154	1,086	419
Other	2,125	2,221	3,947	3,905
Total noninterest income	34,673	36,919	69,548	65,651
NONINTEREST EXPENSE:
Salaries, commissions and employee benefits	35,046	30,814	69,977	60,456
Net occupancy expense	3,241	3,101	6,388	6,128
Equipment expense	2,177	2,010	4,341	4,085
FDIC insurance premiums	766	463	1,467	508
ATM, interchange and credit card expenses	3,039	2,610	5,811	5,595
Professional and service fees	2,392	2,497	4,531	5,090
Printing, stationery and supplies	489	533	814	1,099
Operational and other losses	534	728	821	1,304
Software amortization and expense	2,829	2,010	5,448	4,034
Amortization of intangible assets	412	508	824	1,017
Other	8,449	8,047	16,676	19,324
Total noninterest expense	59,374	53,321	117,098	108,640
EARNINGS BEFORE INCOME TAXES	67,454	64,133	135,426	108,599
INCOME TAX EXPENSE	11,075	10,663	22,129	17,898
NET EARNINGS	$ 56,379	$ 53,470	$ 113,297	$ 90,701
NET EARNINGS PER SHARE, BASIC	$ 0.40	$ 0.38	$ 0.80	$ 0.64
NET EARNINGS PER SHARE, DILUTED	0.39	0.38	0.79	0.64
DIVIDENDS PER SHARE	$ 0.15	$ 0.13	$ 0.28	$ 0.25

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Earnings - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
NET EARNINGS	$ 56,379	$ 53,470	$ 113,297	$ 90,701
OTHER ITEMS OF COMPREHENSIVE EARNINGS:
Change in unrealized gain on investment securities available-for-sale, before income taxes	24,659	36,524	(42,111)	109,561
Reclassification adjustment for realized gains on investment securities included in net earnings, before income taxes	(5)	(1,512)	(813)	(3,574)
Total other items of comprehensive earnings	24,654	35,012	(42,924)	105,987
Income tax benefit (expense) related to:
Change in unrealized gain on investment securities available-for-sale	(5,178)	(7,670)	8,843	(23,008)
Reclassification adjustment for realized gains on investment securities included in net earnings	1	318	172	751
Total income tax benefit (expense)	(5,177)	(7,352)	9,015	(22,257)
COMPREHENSIVE EARNINGS	$ 75,856	$ 81,130	$ 79,388	$ 174,431

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Deferred Compensation [Member]	Accumulated Other Comprehensive Earnings (Losses) [Member]
Beginning Balance at Dec. 31, 2019	$ 1,227,197	$ 1,359	$ 450,676	$ 707,656	$ (8,222)	$ 8,222	$ 67,506
Beginning Balance, Shares at Dec. 31, 2019		135,891,755
Treasury Stock, Beginning Balance, Shares at Dec. 31, 2019					(927,408)
Stock issued in acquisition of TB&T Bancshares, Inc.	220,273	$ 63	220,210
Stock issued in acquisition of TB&T Bancshares, Inc., Shares		6,275,574
Net earnings (unaudited)	90,701			90,701
Stock option exercises (unaudited)	2,481	$ 1	2,480
Stock option exercises, Shares		160,720
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited)	913		913
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited), Shares		32,149
Cash dividends declared	(35,527)			(35,527)
Change in unrealized gain in investment securities available-for-sale, net of related income taxes (unaudited)	83,730						83,730
Shares purchased in connection with directors' deferred compensation plan, net (unaudited)	(8,008)	$ (3)	(8,005)		$ (475)	475
Shares purchased in connection with directors' deferred compensation plan, net (unaudited), Shares		(324,802)			(4,610)
Stock option expense (unaudited)	689		689
Shares repurchased under stock repurchase authorization (unaudited)	(8,008)	$ (3)	(8,005)
Shares repurchased under stock repurchase authorization (unaudited), Shares		(324,802)
Ending Balance at Jun. 30, 2020	$ 1,582,449	$ 1,420	666,963	762,830	$ (8,697)	8,697	151,236
Ending Balance, Shares at Jun. 30, 2020		142,035,396
Treasury Stock, Ending Balance, Shares at Jun. 30, 2020	(932,018)				(932,018)
Beginning Balance at Mar. 31, 2020	$ 1,526,362	$ 1,423	673,535	727,828	$ (8,437)	8,437	123,576
Beginning Balance, Shares at Mar. 31, 2020		142,314,930
Treasury Stock, Beginning Balance, Shares at Mar. 31, 2020					(928,417)
Net earnings (unaudited)	53,470			53,470
Stock option exercises (unaudited)	289		289
Stock option exercises, Shares		16,532
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited)	795		795
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited), Shares		28,736
Cash dividends declared	(18,468)			(18,468)
Change in unrealized gain in investment securities available-for-sale, net of related income taxes (unaudited)	27,660						27,660
Shares purchased in connection with directors' deferred compensation plan, net (unaudited)					$ (260)	260
Shares purchased in connection with directors' deferred compensation plan, net (unaudited), Shares					(3,601)
Stock option expense (unaudited)	349		349
Ending Balance at Jun. 30, 2020	$ 1,582,449	$ 1,420	666,963	762,830	$ (8,697)	8,697	151,236
Ending Balance, Shares at Jun. 30, 2020		142,035,396
Treasury Stock, Ending Balance, Shares at Jun. 30, 2020	(932,018)				(932,018)
Beginning Balance at Dec. 31, 2020	$ 1,678,190	$ 1,422	669,644	836,729	$ (9,126)	9,126	170,395
Beginning Balance, Shares at Dec. 31, 2020		142,161,834
Treasury Stock, Beginning Balance, Shares at Dec. 31, 2020	(938,591)				(938,591)
Net earnings (unaudited)	$ 113,297			113,297
Stock option exercises (unaudited)	2,618	$ 2	2,616
Stock option exercises, Shares		165,371
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited)	(663)		(663)
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited), Shares		32,569
Cash dividends declared	(39,855)			(39,855)
Change in unrealized gain in investment securities available-for-sale, net of related income taxes (unaudited)	(33,909)						(33,909)
Shares purchased in connection with directors' deferred compensation plan, net (unaudited)					$ (515)	515
Shares purchased in connection with directors' deferred compensation plan, net (unaudited), Shares					(38)
Stock option expense (unaudited)	691		691
Shares repurchased under stock repurchase authorization (unaudited), Shares		324,802
Ending Balance at Jun. 30, 2021	$ 1,720,369	$ 1,424	672,288	910,171	$ (9,641)	9,641	136,486
Ending Balance, Shares at Jun. 30, 2021		142,359,774
Treasury Stock, Ending Balance, Shares at Jun. 30, 2021	(938,629)				(938,629)
Beginning Balance at Mar. 31, 2021	$ 1,665,428	$ 1,423	671,849	875,147	$ (9,385)	9,385	117,009
Beginning Balance, Shares at Mar. 31, 2021		142,285,611
Treasury Stock, Beginning Balance, Shares at Mar. 31, 2021					(938,004)
Net earnings (unaudited)	56,379			56,379
Stock option exercises (unaudited)	714	$ 1	713
Stock option exercises, Shares		40,847
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited)	(646)		(646)
Restricted stock grant (unaudited) Restricted stock grant/fortfeiture, net (unaudited), Shares		33,316
Cash dividends declared	(21,355)			(21,355)
Change in unrealized gain in investment securities available-for-sale, net of related income taxes (unaudited)	19,477						19,477
Shares purchased in connection with directors' deferred compensation plan, net (unaudited)					$ (256)	256
Shares purchased in connection with directors' deferred compensation plan, net (unaudited), Shares					(625)
Stock option expense (unaudited)	372		372
Ending Balance at Jun. 30, 2021	$ 1,720,369	$ 1,424	$ 672,288	$ 910,171	$ (9,641)	$ 9,641	$ 136,486
Ending Balance, Shares at Jun. 30, 2021		142,359,774
Treasury Stock, Ending Balance, Shares at Jun. 30, 2021	(938,629)				(938,629)

Consolidated Statements of Sh_2

Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Cash dividend per share	$ 0.15	$ 0.13	$ 0.28	$ 0.25
Retained Earnings [Member]
Cash dividend per share	$ 0.15	$ 0.13	$ 0.28	$ 0.25

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	$ 113,297	$ 90,701
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	6,407	5,935
Provision for credit losses	(3,203)	18,550
Securities premium amortization, net	30,288	17,018
Discount accretion on purchased loans	(1,181)	(1,376)
Gain on sale of assets, net	(1,088)	(3,719)
Deferred federal income tax (expense) benefit	814	(407)
Change in loans held-for-sale	20,899	(36,018)
Change in other assets	(4,125)	(16,452)
Change in other liabilities	(13,792)	38,274
Total adjustments	35,019	21,805
Net cash provided by operating activities	148,316	112,506
CASH FLOWS FROM INVESTING ACTIVITIES:
Cash received in acquisition of TB&T Bancshares, Inc.		61,028
Activity in available-for-sale securities:
Sales	10,631	252,958
Maturities	8,037,370	5,654,371
Purchases	(9,130,287)	(6,392,611)
Net increase in loans held-for-investment	(130,765)	(613,201)
Purchases of bank premises and equipment	(11,640)	(7,681)
Proceeds from sale of bank premises and equipment and other assets	494	1,144
Net cash used in investing activities	(1,224,197)	(1,043,992)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in noninterest-bearing deposits	444,341	638,726
Net increase in interest-bearing deposits	661,536	365,985
Net increase in borrowings	119,876	67,868
Common stock transactions:
Proceeds from stock option exercises	2,618	2,481
Dividends paid	(36,982)	(33,371)
Repurchase of stock		(8,008)
Net cash provided by financing activities	1,191,389	1,033,681
NET INCREASE IN CASH AND CASH EQUIVALENTS	115,508	102,195
CASH AND CASH EQUIVALENTS, beginning of period	729,084	282,604
CASH AND CASH EQUIVALENTS, end of period	844,592	384,799
SUPPLEMENTAL INFORMATION AND NONCASH TRANSACTIONS:
Interest paid	3,500	10,246
Federal income taxes paid	19,263
Transfer of loans and bank premises to other real estate	283	45
Investment securities purchased but not settled	189,838	33,553
Restricted stock grant (forfeiture)	$ (663)	913
Stock issued in acquisition of TB&T Bancshares, Inc.		$ 220,273

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 1 – Summary of Significant Accounting Policies Nature of Operations First Financial Bankshares, Inc. (a Texas corporation) (“Bankshares”, “Company,” “we” or “us”) is a financial holding company which owns all of the capital stock of one bank with 78 locations located in Texas as of June 30, 2021. The Company’s subsidiary bank is First Financial Bank, N.A. The Company’s primary source of revenue is providing loans and banking services to consumers and commercial customers in the market area in which First Financial Bank, N.A. is located. In addition, the Company also owns First Financial Trust & Asset Management Company, N.A., First Financial Insurance Agency, Inc. and First Technology Services, Inc. Basis of Presentation A summary of significant accounting policies of the Company and its subsidiaries applied in the preparation of the accompanying consolidated financial statements follows. The accounting principles followed by the Company and the methods of applying them are in conformity with both United States generally accepted accounting principles (“GAAP”) and prevailing practices of the banking industry. The Company evaluated subsequent events for potential recognition through the date the consolidated financial statements were issued. Use of Estimates in Preparation of Financial Statements The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The Company’s significant estimates include its allowance for credit losses and its valuation of financial instruments. Consolidation The accompanying consolidated financial statements include the accounts of the Company and its subsidiaries, all of which are wholly-owned. All significant intercompany accounts and transactions have been eliminated. Stock Repurchase On March 12, 2020, the Company’s Board of Directors authorized the repurchase of up to 4,000,000 common shares through September 30, 2021. On July 27, 2021, the Company’s Board of Directors renewed the prior authorization and authorized the repurchase of up to 5,000,000 common shares through July 31, 2023. The stock repurchase plan authorizes management to repurchase and retire the stock at such time as repurchases and retirements are considered beneficial to the Company and stockholders. Any repurchase of stock will be made through the open market, block trades or in privately negotiated transactions in accordance with applicable laws and regulations. Under the repurchase plan, there is no minimum number of shares that the Company is required to repurchase. Through June 30, 2021, 324,802 shares were repurchased and retired (all during the months of March and April 2020) totaling $8,008,000 under this repurchase plan. Acquisition On January 1, 2020, the Company acquired 100% of the outstanding capital stock of TB&T Bancshares, Inc. through the merger of a wholly-owned subsidiary with and into TB&T Bancshares, Inc. Following such merger, TB&T Bancshares, Inc. and its wholly-owned subsidiary, The Bank & Trust of Bryan/College Station, Texas were merged into the Company and First Financial Bank, N.A., respectively. The results of operations of TB&T Bancshares, Inc. subsequent to the acquisition date, are included in the consolidated earnings of the Company. See Note 10 for additional information. Adoption of New Accounting Standards On January 1, 2020, ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments held-to-maturity off-balance-sheet available-for-sale available-for-sale On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was signed by the President of the United States that included an option for entities to delay the implementation of ASC 326 until the earlier of the termination date of the national emergency declaration by the President or December 31, 2020. Under this option, the Company elected to delay its implementation of CECL and calculated and recorded the provision for credit losses through the nine-months ended September 30, 2020 under the incurred loss model. At December 31, 2020, the Company elected to adopt ASC 326, effective as of January 1, 2020, through a transition charge to retained earnings of $589,000 ($466,000 net of applicable income taxes). This transition adjustment was comprised of a decrease of $619,000 in allowance for credit losses and an increase of $1,208,000 in the reserve for unfunded commitments. With the adoption of ASC 326, we revised certain accounting policies and implemented certain accounting policy elections which are described below. For the 2020 interim reporting periods, the allowance for credit losses were based on the incurred loss methodology in accordance with accounting policies disclosed in Note 1 of the Consolidated Financial Statements included in the Company’s 2019 Form 10-K. The Company adopted ASC 326 using the modified retrospective method for all financial assets measured at amortized cost, net investment in leases and OBS credit exposures. The Company adopted ASC 326 using the prospective transition approach for securities for which other-than-temporary impairment had been recognized prior to January 1, 2020. As a result, the amortized cost basis remains the same before and after the effective date of ASC 326. The effective interest rate on these debt securities was not changed. The Company adopted ASC 326 using the prospective transition approach for financial assets purchased with credit deterioration (“PCD”) that were previously classified as purchased credit impaired (“PCI”) and accounted for under ASC 310-30. Other Recently Issued and Effective Authoritative Accounting Guidance ASU 2017-04, 2017-04 2017-04 ASU 2018-13, “ Fair Value Measurement (Topic 820). – Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. ” 2018-13 2018-13 2018-13 ASU 2019-12, 2019-12, step-up 2019-12 2019-12 ASU 2020-04, 2020-04 2020-04 2020-04 2020-04 ASU 2021-01, 2021-01 2021-01 2021-01 2021-01 Investment Securities Management classifies debt securities as held-to-maturity, available-for-sale, held-to-maturity held-to-maturity available-for-sale Interest income includes amortization of purchase premiums and discounts over the period to maturity using a level-yield method, except for premiums on callable securities, which are amortized to their earliest call date. Realized gains and losses are recorded on the sale of securities in noninterest income. The Company has made a policy election to exclude accrued interest from the amortized cost basis of securities and report accrued interest separately in other assets on the consolidated balance sheets. A security is placed on non-accrual non-accrual six-months The Company records its available-for-sale The Company’s investment portfolio currently consists of obligations of state and political subdivisions, mortgage pass-through securities, corporate bonds and general obligation or revenue based municipal bonds. Pricing for such securities is generally readily available and transparent in the market. The Company utilizes independent third-party pricing services to value its investment securities, which the Company reviews as well as the underlying pricing methodologies for reasonableness and to ensure such prices are aligned with pricing matrices. The Company validates prices supplied by the independent pricing services by comparison to prices obtained from other third-party sources on a quarterly basis. Allowance for Credit Losses – Available-for-Sale For available-for-sale charged-off available-for-sale Management has made the accounting policy election to exclude accrued interest receivable on available-for-sale Available-for-sale charged-off Prior to the adoption of ASC 326, declines in the fair value of securities below their cost that were deemed to be other-than-temporary were reflected in earnings as realized losses. In estimating other-than-temporary impairment losses prior to the adoption, management considered, among other things, the length of time and the extent to which the fair value had been less than cost, the financial condition and near-term prospects of the issuer and the intent and our ability to retain our investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value.​​​​​​​ Allowance for Credit Losses – Held-to-Maturity The allowance for credit losses on held-to-maturity held-to-maturity Held-to-maturity charged-off held-to-maturity held-to-maturity At June 30, 2021, 2020 and December 31, 2020, the Company held no securities that were classified as held-to-maturity. Loans Held-for-Investment Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost, net of the allowance for credit losses. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts, fair value hedge accounting adjustments, deferred loan fees and costs. The Company has made a policy election to exclude accrued interest from the amortized cost basis of loans and report accrued interest separately from the related loan balance in other assets on the condensed consolidated balance sheets. Interest on loans is calculated by using the simple interest method on daily balances of the principal amounts outstanding. The Company defers and amortizes net loan origination fees and costs as an adjustment to yield. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans are placed on non-accrual non-accrual non-accrual non-accrual Prior to the adoption of ASC 326, loans were reported as impaired when, based on then current information and events, it was probable we would be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impairment was evaluated in total for smaller-balance loans of a similar nature and on an individual loan basis for other loans. If a loan was impaired, a specific valuation allowance was allocated, if necessary, so that the loan was reported net, at the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral if repayment was expected solely from the collateral. Interest payments on impaired loans were typically applied to principal unless collectability of the principal amount was reasonably assured, in which case interest was recognized on a cash basis. Impaired loans, or portions thereof, were charged off when deemed uncollectible. Further information regarding our accounting policies related to past due loans, non-accrual Acquired Loans Loans acquired in connection with acquisitions are recorded at their acquisition-date fair value. The allowance for credit losses related to the acquired loan portfolio is not carried over. Acquired loans are classified into two categories based on the credit risk characteristics of the underlying borrowers as either purchased credit deteriorated (“PCD”) loans, or loans with no evidence of credit deterioration (“non-PCD”). PCD loans are defined as a loan or pool of loans that have experienced more-than-insignificant credit deterioration since the origination date. The Company uses a combination of individual and pooled review approaches to determine if acquired loans are PCD. At acquisition, the Company considers a number of factors to determine if an acquired loan or pool of loans has experienced more-than-insignificant credit deterioration. The initial allowance related to PCD loans that share similar risk characteristics is established using a pooled approach. The Company uses either a discounted cash flow or weighted average remaining life method to determine the required level of the allowance. PCD loans that were classified as non-accrual For PCD loans, an initial allowance is established on the acquisition date and combined with the fair value of the loan to arrive at acquisition date amortized cost. Subsequent to the acquisition date, the initial allowance for credit losses on PCD loans will increase or decrease based on future evaluations, with changes recognized in the provision for credit losses. Non-PCD Determining the fair value of the acquired loans involves estimating the principal and interest payment cash flows expected to be collected on the loans and discounting those cash flows at a market rate of interest. Management considers a number of factors in evaluating the acquisition-date fair value including the remaining life, interest rate profile, market interest rate environment, payment schedules, risk ratings, probability of default and loss given default, and estimated prepayment rates. For PCD loans, the non-credit non-credit non-PCD Prior to the adoption of ASC 326, loans acquired in a business combination that had evidence of credit impairment and for which it was probable, at acquisition, that the Company would be unable to collect all contractually required payments receivable were considered PCI. PCI loans were accounted for individually or aggregated into pools of loans based on common risk characteristics such as credit grade, loan type, and date of origination. Allowance for Credit Losses - Loans The allowance for credit losses (“allowance” or “ACL”) is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans. The ACL represents an amount which, in management’s judgement, is adequate to absorb the lifetime expected credit losses that may be experienced on outstanding loans at the balance sheet date based on the evaluation of the size and current risk characteristics of the loan portfolio, past events, current conditions, reasonable and supportable forecasts of future economic conditions and prepayment experience. The allowance for credit losses is measured and recorded upon the initial recognition of a financial asset. Determination of the adequacy of the allowance is inherently complex and requires the use of significant and highly subjective estimates. Loans are charged-off charged-off charged-off. The Company’s methodology for estimating the allowance includes: (1) a collective quantified reserve that reflects the Company’s historical default and loss experience adjusted for expected economic conditions throughout a reasonable and supportable forecast period, including the Company’s expected prepayment and curtailment rates; (2) collective qualitative factors that consider concentrations of the loan portfolio, expected changes to the economic forecasts, notable changes in a loan segments economic environment, large relationships, early delinquencies, and factors related to credit administrations, including, among others, loan-to-value In calculating the allowance for credit losses, most loans are segmented into pools based upon similar characteristics and risk profiles. Common characteristics and risk profiles include the type/purpose of loan, underlying collateral, geographical similarity and historical/expected credit loss patterns. In developing these loan pools for the purposes of modeling expected credit losses, we also analyzed the degree of correlation in how loans within each portfolio respond when subjected to varying economic conditions and scenarios as well as other portfolio stress factors. For modeling purposes, our loan portfolio segments include Commercial and Industrial (“C&I”), Municipal, Agricultural, Construction and Development, Farm, Non-Owner Non-Auto. The Company applies two methodologies to estimate the allowance on its pooled portfolio segments; discounted cash flows method and weighted average remaining life method. Allowance estimates on the following portfolio segments are calculated using the discounted cash flows method: C&I, Municipal, Construction and Development, Farm, Non-Owner Non-Auto. one-year In some cases, management may determine that an individual loan exhibits unique risk characteristics which differentiate the loan from other loans within our loan pools. In such cases, the loans are evaluated for expected credit losses on an individual basis and excluded from the collective evaluation. Specific allocations of the allowance for credit losses are determined by analyzing the borrower’s ability to repay amounts owed, collateral deficiencies, the relative risk rating of the loan and economic conditions affecting the borrower’s industry, among other things. A loan is considered to be collateral dependent when, based upon management’s assessment, the borrower is experiencing financial difficulty and repayment is expected to be provided substantially through the sale of the collateral. In such cases, expected credit losses are based on the fair value of the collateral at the measurement date, adjusted for estimated selling costs if satisfaction of the loan depends on the sale of the collateral. We reevaluate the fair value of collateral supporting collateral dependent loans on an ongoing basis. Management qualitatively adjusts model results for risk factors that are not considered within our modeling processes but are nonetheless relevant in assessing the expected credit losses within our loan pools. These qualitative factor (“Q-Factor”) Q-Factor non-accrual non-collateral Management believes it uses relevant information available to make determinations about the allowance and that it has established the existing allowance in accordance with GAAP. However, the determination of the allowance requires significant judgment, and estimates of expected lifetime losses in the loan portfolio can vary significantly from the amounts actually observed. While management uses available information to recognize expected losses, future additions to the allowance may be necessary based on changes in the loans comprising the portfolio, changes in the current and forecasted economic conditions, changes to the interest rate environment which may directly impact prepayment and curtailment rate assumptions, and changes in the financial condition of borrowers. The adoption of the CECL standard did not result in a significant change to any other credit risk management and monitoring processes, including identification of past due or delinquent borrowers, non-accrual charge-off Allowance for Credit Losses - Off-Balance-Sheet/Reserve The allowance for credit losses on off-balance-sheet Other Real Estate Other real estate owned is foreclosed property held pending disposition and is initially recorded at fair value, less estimated costs to sell. At foreclosure, if the fair value of the real estate, less estimated costs to sell, is less than the Company’s recorded investment in the related loan, a write-down is recognized through a charge to the allowance for credit losses. Any subsequent reduction in value is recognized by a charge to income. Operating and holding expenses of such properties, net of related income, and gains and losses on their disposition are included in net gain (loss) on sale of foreclosed assets as incurred. Bank Premises and Equipment Bank premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization are computed principally on a straight-line basis over the estimated useful lives of the related assets. Leasehold improvements are amortized over the life of the respective lease or the estimated useful lives of the improvements, whichever is shorter. Business Combinations, Goodwill and Other Intangible Assets The Company accounts for all business combinations under the purchase method of accounting. Tangible and intangible assets and liabilities of the acquired entity are recorded at fair value. Intangible assets with finite useful lives represent the future benefit associated with the acquisition of the core deposits and are amortized over seven years, utilizing a method that approximates the expected attrition of the deposits. Goodwill with an indefinite life is not amortized, but rather tested annually for impairment as of June 30 each year. There was no impairment recorded for the three or six-months Securities Sold Under Agreements To Repurchase Securities sold under agreements to repurchase, which are classified as borrowings, generally mature within one to four days from the transaction date. Securities sold under agreements to repurchase are reflected at the amount of the cash received in connection with the transaction. The Company may be required to provide additional collateral based on the estimated fair value of the underlying securities. Segment Reporting The Company has determined that its banking regions meet the aggregation criteria of the current authoritative accounting guidance since each of its banking regions offer similar products and services, operate in a similar manner, have similar customers and report to the same regulatory authority, and therefore operate one line of business (community banking) located in a single geographic area (Texas). Statements of Cash Flows For purposes of reporting cash flows, cash and cash equivalents includes cash on hand, amounts due from banks, including interest-bearing demand deposits in banks with original maturity of 90 days or less, and federal funds sold. Accumulated Other Comprehensive Earnings (Loss) Unrealized net gains on the Company’s available-for-sale Income Taxes The Company’s provision for income taxes is based on income before income taxes adjusted for permanent differences between financial reporting and taxable income. Deferred tax assets and liabilities are determined using the liability (or balance sheet) method. Under this method, the net deferred tax asset or liability is determined based on the tax effects of the temporary differences between the book and tax bases of the various balance sheet assets and liabilities and gives current recognition to changes in tax rates and laws. Stock Based Compensation The Company grants stock options for a fixed number of shares to employees with an exercise price equal to the fair value of the shares at the grant date. The grant date fair value is amortized over the shorter of the service period or vesting period which generally is six years. The Company also grants restricted stock for a fixed number of shares. The grant date fair value is amortized over the vesting period which generally is one to three years. See Note 8 for further information. Advertising Costs Advertising costs are expensed as incurred. Per Share Data Net earnings per share (“EPS”) are computed by dividing net earnings by the weighted average number of common shares outstanding during the period. The Company calculates dilutive EPS assuming all outstanding stock options to purchase common shares and unvested restricted stock shares have been exercised and/or vested at the beginning of the year (or the time of issuance, if later.) The dilutive effect of the outstanding options and restricted stock is reflected by application of the treasury stock method, whereby the proceeds from the exercised options and unearned compensation for both restricted stock and stock options are assumed to be used to purchase common shares at the average market price during the respective period. There were no anti-dilutive shares for the three or six-months six-months Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the three-months ended June 30, 2021: Net earnings per share, basic $ 56,379 142,245,555 $ 0.40 Effect of stock options and stock grants — 919,056 (0.01 ) Net earnings per share, diluted $ 56,379 143,164,611 $ 0.39 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the six-months Net earnings per share, basic $ 113,297 142,196,190 $ 0.80 Effect of stock options and stock grants — 906,418 (0.01 ) Net earnings per share, diluted $ 113,297 143,102,608 $ 0.79 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the three-months ended June 30, 2020: Net earnings per share, basic $ 53,470 141,973,522 $ 0.38 Effect of stock options and stock grants — 480,561 — Net earnings per share, diluted $ 53,470 142,454,083 $ 0.38 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the six-months Net earnings per share, basic $ 90,701 142,045,779 $ 0.64 Effect of stock options and stock grants — 473,529 — Net earnings per share, diluted $ 90,701 142,519,308 $ 0.64

Securities

Securities	6 Months Ended
	Jun. 30, 2021
Cash and Cash Equivalents [Abstract]
Securities	Note 2 - Securities Debt securities have been classified in the consolidated balance sheets according to management’s intent. The amortized cost, related gross unrealized gains and losses, allowance for credit losses and the fair value of available-for-sale June 30, 2021 Gross Gross Amortized Unrealized Unrealized Estimated Cost Basis Holding Gains Holding Losses Fair Value Securities available-for-sale: Obligations of states and political subdivisions $ 2,490,468 $ 125,612 $ (993 ) $ 2,615,087 Residential mortgage-backed securities 2,471,278 38,619 (5,711 ) 2,504,186 Commercial mortgage-backed securities 405,146 15,822 — 420,968 Corporate bonds and other 38,297 91 (581 ) 37,807 Total securities available-for-sale $ 5,405,189 $ 180,144 $ (7,285 ) $ 5,578,048 June 30, 2020 Gross Gross Amortized Unrealized Unrealized Estimated Cost Basis Holding Gains Holding Losses Fair Value Securities available-for-sale: U.S. Treasury securities $ 10,083 $ 40 $ (1 ) $ 10,122 Obligations of states and political subdivisions 1,836,572 113,757 (50 ) 1,950,279 Residential mortgage-backed securities 1,517,139 54,652 (118 ) 1,571,673 Commercial mortgage-backed securities 559,062 23,159 (1 ) 582,220 Corporate bonds and other 4,398 171 — 4,569 Total securities available-for-sale $ 3,927,254 $ 191,779 $ (170 ) $ 4,118,863 December 31, 2020 Gross Gross Amortized Unrealized Unrealized Estimated Cost Basis Holding Gains Holding Losses Fair Value Securities available-for-sale: Obligations of states and political subdivisions $ 2,283,616 $ 143,339 $ (79 ) $ 2,426,876 Residential mortgage-backed securities 1,421,922 50,473 (115 ) 1,472,280 Commercial mortgage-backed securities 467,243 22,077 (4 ) 489,316 Corporate bonds and other 4,398 159 — 4,557 Total securities available-for-sale $ 4,177,179 $ 216,048 $ (198 ) $ 4,393,029 The Company did not hold any securities classified as held-to-maturity The Company invests in mortgage-backed securities that have expected maturities that differ from their contractual maturities. These differences arise because borrowers may have the right to call or prepay obligations with or without a prepayment penalty. These securities include collateralized mortgage obligations (CMOs) and other asset backed securities. The expected maturities of these securities at June 30, 2021 and 2020, and December 31, 2020, were computed by using scheduled amortization of balances and historical prepayment rates. The amortized cost and estimated fair value of available-for-sale Amortized Estimated Cost Basis Fair Value Due within one year $ 297,211 $ 301,535 Due after one year through five years 2,493,104 2,586,178 Due after five years through ten years 2,506,074 2,581,554 Due after ten years 108,800 108,781 Total $ 5,405,189 $ 5,578,048 The following tables disclose the Company’s investment securities that have been in a continuous unrealized-loss Less than 12 Months 12 Months or Longer Total June 30, 2021 Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized Obligations of states and political subdivisions $ 170,483 $ 992 $ — $ — $ 170,483 $ 992 Residential mortgage-backed securities 712,100 5,706 2,478 6 714,578 5,712 Commercial mortgage-backed securities 866 — — — 866 — Corporate bonds and other 33,318 581 — — 33,318 581 Total $ 916,767 $ 7,279 $ 2,478 $ 6 $ 919,245 $ 7,285 Less than 12 Months 12 Months or Longer Total June 30, 2020 Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized U.S. Treasury securities $ 5,055 $ 1 $ — $ — $ 5,055 $ 1 Obligations of states and political subdivisions 18,249 50 — — 18,249 50 Residential mortgage-backed securities 12,590 45 6,454 73 19,044 118 Commercial mortgage-backed securities 4,936 1 — — 4,936 1 Total $ 40,830 $ 97 $ 6,454 $ 73 $ 47,284 $ 170 Less than 12 Months 12 Months or Longer Total December 31, 2020 Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized Obligations of state and political subdivisions $ 25,214 $ 79 $ — $ — $ 25,214 $ 79 Residential mortgage-backed securities 36,017 96 3,156 19 39,173 115 Commercial mortgage-backed securities 16,218 4 — — 16,218 4 Total $ 77,449 $ 179 $ 3,156 $ 19 $ 80,605 $ 198 The number of investments in an unrealized loss position totaled 77 at June 30, 2021. Any unrealized losses in the obligations of state and political subdivisions, residential and commercial mortgage-backed and asset-backed investment securities at June 30, 2021 and 2020, and December 31, 2020, are due to changes in interest rates and not credit-related events. As such, no allowance for credit losses is required on these securities at June 30, 2021 and 2020, and December 31, 2020. Unrealized losses on investment securities are expected to recover over time as these securities approach maturity. Our mortgage related securities are backed by GNMA, FNMA and FHLMC or are collateralized by securities backed by these agencies. At June 30, 2021, 76.39% of our available-for-sale At June 30, 2021, $3,222,472,000 of the Company’s securities were pledged as collateral for public or trust fund deposits, repurchase agreements, a borrowing line with the Federal Reserve Bank of Dallas and for other purposes required or permitted by law. During the three-months ended June 30, 2021, there were calls of investment securities that were classified as available-for-sale. available-for-sale During the six-months available-for-sale six-month six-month six-month The specific identification method was used to determine cost in order to compute the realized gains and losses.

Loans Held for Investment and A

Loans Held for Investment and Allowance for Loan Losses	6 Months Ended
	Jun. 30, 2021
Receivables [Abstract]
Loans Held for Investment and Allowance for Credit Losses	Note 3 – Loans Held-for-Investment In conjunction with the adoption of ASC 326, the Company expanded its four loan portfolios into ten portfolio segments. For the periods ended June 30, 2021 and December 31, 2020, the following tables outline the Company’s loan portfolio by the ten portfolio segments where applicable. For disclosures related to the period ended June 30, 2020, management has elected to maintain its previously disclosed loan segments. Loans held-for-investment June 30, December 31, 2021 2020 2020 Commercial: C&I* $ 983,103 $ N/A $ 1,131,382 Municipal 179,356 N/A 181,325 Total Commercial 1,162,459 1,509,454 1,312,707 Agricultural 95,212 97,448 94,864 Real Estate: Construction & Development 550,928 N/A 553,959 Farm 185,288 N/A 152,237 Non-Owner 673,608 N/A 617,686 Owner Occupied CRE 820,055 N/A 746,974 Residential 1,328,474 N/A 1,248,409 Total Real Estate 3,558,353 3,235,208 3,319,265 Consumer: Auto 383,764 N/A 353,595 Non-Auto 104,814 N/A 90,602 Total Consumer 488,578 410,957 444,197 Total Loans 5,304,602 5,253,067 5,171,033 Less: Allowance for credit losses (62,138 ) (68,947 ) (66,534 ) Loans, net $ 5,242,464 $ 5,184,120 $ 5,104,499 * All disclosures for the C&I loan segment include PPP loan balances, net of deferred loan fees, as disclosed on the face of the balance sheet on page 4. Outstanding loan balances at June 30, 2021 and 2020, and December 31, 2020, are net of unearned income, including net deferred loan fees. Our subsidiary bank has established a line of credit with the Federal Home Loan Bank of Dallas (“FHLB”) to provide liquidity and meet pledging requirements for those customers eligible to have securities pledged to secure certain uninsured deposits. At June 30, 2021, $3,311,924,000 in loans held by our bank subsidiary were subject to blanket liens as security for this line of credit. At June 30, 2021, there was no balance outstanding under this line of credit. The Company’s non-accrual June 30, December 31, 2021 2020 2020 Non-accrual $ 29,786 $ 39,320 $ 42,619 Loans still accruing and past due 90 days or more — 92 113 Troubled debt restructured loans still accruing* 23 25 24 Total $ 29,809 $ 39,437 $ 42,756 * Troubled debt restructured loans of $7,305,000, $7,275,000 and $7,407,000, whose interest collection, after considering economic and business conditions and collection efforts, is doubtful are included in non-accrual The Company had $30,114,000, $39,724,000 and $42,898,000 in non-accrual, Non-accrual June 30, December 31, 2021 2020 2020 Commercial: C&I $ 3,587 $ N/A $ 5,015 Municipal — N/A — Total Commercial 3,587 4,618 5,015 Agricultural 1,055 1,056 1,076 Real Estate: Construction & Development 1,520 N/A 3,838 Farm 1,791 N/A 7,299 Non-Owner 6,584 N/A 5,243 Owner Occupied CRE 8,976 N/A 10,797 Residential 5,901 N/A 8,851 Total Real Estate 24,772 33,170 36,028 Consumer: Auto 329 N/A 407 Non-Auto 43 N/A 93 Total Consumer 372 476 500 Total $ 29,786 $ 39,320 $ 42,619 No significant additional funds are committed to be advanced in connection with non-accrual Summary information on the allowance for credit losses for the three and six-months Three-months ended June 30, 2021 C&I Municipal Agricultural Construction Farm Beginning balance $ 12,323 $ 2,191 $ 1,985 $ 13,246 $ 1,223 Provision for loan losses (2,327 ) (1,603 ) (667 ) 2,386 (617 ) Recoveries 308 — 15 — 1 Charge-offs (118 ) — (21 ) — — Ending balance $ 10,186 $ 588 $ 1,312 $ 15,632 $ 607 Three-months ended June 30, 2021 (continued) Non-Owner Owner Residential Auto Non-Auto Total Beginning balance $ 9,492 $ 9,878 $ 11,189 $ 1,068 $ 379 $ 62,974 Provision for loan losses 901 517 26 257 88 (1,039 ) Recoveries 39 4 64 103 61 595 Charge-offs — — (45 ) (162 ) (46 ) (392 ) Ending balance $ 10,432 $ 10,399 $ 11,234 $ 1,266 $ 482 $ 62,138 Six-months C&I Municipal Agricultural Construction Farm Beginning balance $ 13,609 $ 1,552 $ 1,255 $ 13,512 $ 1,876 Provision for loan losses (3,566 ) (964 ) 54 2,118 (1,279 ) Recoveries 531 — 24 2 10 Charge-offs (388 ) — (21 ) — — Ending balance $ 10,186 $ 588 $ 1,312 $ 15,632 $ 607 Six-months Non-Owner Owner Residential Auto Non- Total Beginning balance $ 8,391 $ 12,347 $ 12,601 $ 1,020 $ 371 $ 66,534 Provision for loan losses 1,953 (1,950 ) (1,358 ) 398 126 (4,468 ) Recoveries 94 10 83 176 108 1,038 Charge-offs (6 ) (8 ) (92 ) (328 ) (123 ) (966 ) Ending balance $ 10,432 $ 10,399 $ 11,234 $ 1,266 $ 482 $ 62,138 Three-months ended June 30, 2020 Commercial Agricultural Real Estate Consumer Total Beginning balance $ 11,773 $ 2,154 $ 41,256 $ 5,257 $ 60,440 Provision for loan losses 6,820 361 1,469 50 8,700 Recoveries 540 29 59 73 701 Charge-offs (561 ) — (161 ) (172 ) (894 ) Ending balance $ 18,572 $ 2,544 $ 42,623 $ 5,208 $ 68,947 Six-months Commercial Agricultural Real Estate Consumer Total Beginning balance $ 12,122 $ 1,206 $ 33,974 $ 5,197 $ 52,499 Provision for loan losses 7,615 1,310 9,390 235 18,550 Recoveries 690 30 135 164 1,019 Charge-offs (1,855 ) (2 ) (876 ) (388 ) (3,121 ) Ending balance $ 18,572 $ 2,544 $ 42,623 $ 5,208 $ 68,947 Additionally, the Company records a reserve for unfunded commitments in other liabilities which totaled $6,751,000, $809,000 and $5,486,000 at June 30, 2021 and 2020, and December 31, 2020, respectively. The reversal of provision for credit losses of $1,206,000 reported in the consolidated statement of earnings for the three-months ended June 30, 2021 is the aggregate reversal of provision of loan losses of $1,039,000 and the reversal of provision for unfunded commitments of $167,000. The reversal of provision for credit losses of $3,203,000 reported in the consolidated statement of earnings for the six-months The Company’s loans that are individually evaluated for credit losses (both collateral and non-collateral June 30, 2021 Collateral Collateral Non-Collateral Total Loans Related Related Non-Collateral Total Commercial: C&I $ 1,091 $ 2,496 $ 20,838 $ 24,425 $ 723 $ 3,865 $ 4,588 Municipal — — 885 885 — 275 275 Total Commercial 1,091 2,496 21,723 25,310 723 4,140 4,863 Agricultural 328 727 5,195 6,250 171 1,084 1,255 Real Estate: Construction & Development 1,282 238 9,201 10,721 24 1,075 1,099 Farm 1,697 94 2,745 4,536 — 9 9 Non-Owner 6,444 140 33,707 40,291 15 4,185 4,200 Owner Occupied CRE 5,605 3,371 42,832 51,808 544 2,600 3,144 Residential 3,762 2,139 28,110 34,011 191 2,418 2,609 Total Real Estate 18,790 5,982 116,595 141,367 774 10,287 11,061 Consumer: Auto — 329 1,342 1,671 1 4 5 Non-Auto — 43 353 396 — 2 2 Total Consumer — 372 1,695 2,067 1 6 7 Total $ 20,209 $ 9,577 $ 145,208 $ 174,994 $ 1,669 $ 15,517 $ 17,186 December 31, 2020 Collateral Collateral Non-Collateral Total Loans Related Related Non-Collateral Total Commercial: C&I $ 1,544 $ 3,471 $ 25,629 $ 30,644 $ 799 $ 4,592 $ 5,391 Municipal — — 9,439 9,439 — 1,435 1,435 Total Commercial 1,544 3,471 35,068 40,083 799 6,027 6,826 Agricultural 470 606 5,572 6,648 96 886 982 Real Estate: Construction & Development 1,176 2,661 11,368 15,205 35 617 652 Farm 2,614 4,685 3,349 10,648 654 658 1,312 Non-Owner 4,009 1,234 17,383 22,626 500 1,421 1,921 Owner Occupied CRE 7,279 3,518 51,933 62,730 657 5,172 5,829 Residential 4,347 4,504 28,196 37,047 676 2,431 3,107 Total Real Estate 19,425 16,602 112,229 148,256 2,522 10,299 12,821 Consumer: Auto — 407 1,523 1,930 1 5 6 Non-Auto — 94 440 534 1 1 2 Total Consumer — 501 1,963 2,464 2 6 8 Total $ 21,439 $ 21,180 $ 154,832 $ 197,451 $ 3,419 $ 17,218 $ 20,637 The following table presents the recorded investment with respect to impaired loans, the associated allowance by the applicable portfolio segment and the unpaid contractual principal balance of the impaired loans at June 30, 2020, in accordance with the legacy “incurred loss” methodology disclosure requirements (in thousands): June 30, 2020 Unpaid Recorded Recorded Total Related Year-to- Three- Commercial $ 6,013 $ 739 $ 3,879 $ 4,618 $ 1,250 $ 24,270 $ 23,572 Agricultural 1,287 529 527 1,056 83 219 179 Real Estate 45,703 20,370 12,800 33,170 1,711 17,586 17,107 Consumer 585 — 476 476 2 606 552 Total $ 53,588 $ 21,638 $ 17,682 $ 39,320 $ 3,046 $ 42,681 $ 41,410 The Company’s allowance for loans that are individually evaluated for credit losses and collectively evaluated for credit losses as of June 30, 2021 and December 31, 2020, are summarized in the following table by loan segment (in thousands). Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. June 30, 2021 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 4,588 $ 275 $ 1,255 $ 1,099 $ 9 Loans collectively evaluated for credit losses 5,598 313 57 14,533 598 Total $ 10,186 $ 588 $ 1,312 $ 15,632 $ 607 June 30, 2021 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 4,200 $ 3,144 $ 2,609 $ 5 $ 2 $ 17,186 Loans collectively evaluated for credit losses 6,232 7,255 8,625 1,261 480 44,952 Total $ 10,432 $ 10,399 $ 11,234 $ 1,266 $ 482 $ 62,138 December 31, 2020 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 5,391 $ 1,435 $ 982 $ 652 $ 1,312 Loans collectively evaluated for credit losses 8,218 117 273 12,860 564 Total $ 13,609 $ 1,552 $ 1,255 $ 13,512 $ 1,876 December 31, 2020 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 1,921 $ 5,829 $ 3,107 $ 6 $ 2 $ 20,637 Loans collectively evaluated for credit losses 6,470 6,518 9,494 1,014 369 45,897 Total $ 8,391 $ 12,347 $ 12,601 $ 1,020 $ 371 $ 66,534 The Company’s allowance for loans that are individually evaluated for credit losses and collectively evaluated for credit losses as of June 30, 2020, are summarized in the following table by loan segment in accordance with the legacy “incurred loss” methodology disclosure requirements (in thousands): June 30, 2020 Commercial Agricultural Real Estate Consumer Total Loans individually evaluated for impairment $ 1,250 $ 83 $ 1,711 $ 2 $ 3,046 Loan collectively evaluated for impairment 17,322 2,461 40,912 5,206 65,901 Total $ 18,572 $ 2,544 $ 42,623 $ 5,208 $ 68,947 The Company’s recorded investment in loans as of June 30, 2021 and December 31, 2020, related to the balance in the allowance for credit losses on the basis of the Company’s adopted ASC 326 evaluation methodology follows below (in thousands): June 30, 2021 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 24,425 $ 885 $ 6,250 $ 10,721 $ 4,536 Loans collectively evaluated for credit losses 958,678 178,471 88,962 540,207 180,752 Total $ 983,103 $ 179,356 $ 95,212 $ 550,928 $ 185,288 June 30, 2021 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 40,291 $ 51,808 $ 34,011 $ 1,671 $ 396 $ 174,994 Loans collectively evaluated for credit losses 633,317 768,247 1,294,463 382,093 104,418 5,129,608 Total $ 673,608 $ 820,055 $ 1,328,474 $ 383,764 $ 104,814 $ 5,304,602 December 31, 2020 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 30,644 $ 9,439 $ 6,648 $ 15,205 $ 10,648 Loans collectively evaluated for credit losses 1,100,738 171,886 88,216 538,754 141,589 Total $ 1,131,382 $ 181,325 $ 94,864 $ 553,959 $ 152,237 December 31, 2020 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 22,626 $ 62,730 $ 37,047 $ 1,930 $ 534 $ 197,451 Loans collectively evaluated for credit losses 595,060 684,244 1,211,362 351,665 90,068 4,973,582 Total $ 617,686 $ 746,974 $ 1,248,409 $ 353,595 $ 90,602 $ 5,171,033 The Company’s recorded investment in loans as of June 30, 2020, related to the balance in the allowance for loan losses on the basis of the Company’s legacy “incurred loss” impairment methodology follows below (in thousands): June 30, 2020 Commercial Agricultural Real Estate Consumer Total Loans individually evaluated for impairment $ 4,618 $ 1,056 $ 33,170 $ 476 $ 39,320 Loan collectively evaluated for impairment 1,504,836 96,392 3,202,038 410,481 5,213,747 Total $ 1,509,454 $ 97,448 $ 3,235,208 $ 410,957 $ 5,253,067 From a credit risk standpoint, the Company rates its loans in one of five categories: (i) pass, (ii) special mention, (iii) substandard, (iv) doubtful or (v) loss (which are charged-off). The ratings of loans reflect a judgment about the risks of default and loss associated with the loan. The Company reviews the ratings on our credits as part of our on-going Credits rated special mention show clear signs of financial weaknesses or deterioration in credit worthiness, however, such concerns are not so pronounced that the Company generally expects to experience significant loss within the short-term. Such credits typically maintain the ability to perform within standard credit terms and credit exposure is not as prominent as credits rated more harshly. Credits rated substandard are those in which the normal repayment of principal and interest may be, or has been, jeopardized by reason of adverse trends or developments of a financial, managerial, economic or political nature, or important weaknesses exist in collateral. A protracted workout on these credits is a distinct possibility. Prompt corrective action is therefore required to strengthen the Company’s position, and/or to reduce exposure and to assure that adequate remedial measures are taken by the borrower. Credit exposure becomes more likely in such credits and a serious evaluation of the secondary support to the credit is performed. Credits rated doubtful are those in which full collection of principal appears highly questionable, and which some degree of loss is anticipated, even though the ultimate amount of loss may not yet be certain and/or other factors exist which could affect collection of debt. Based upon available information, positive action by the Company is required to avert or minimize loss. Credits rated doubtful are generally also placed on non-accrual. The following summarizes the Company’s internal ratings of its loans held-for-investment, June 30, 2021 2020 2019 2018 2017 Prior Revolving Total C&I Risk rating: Pass $ 485 $ 316 $ 71 $ 46 $ 22 $ 19 $ — $ 959 Special mention 4 2 1 1 1 — — 9 Substandard 4 6 2 3 — — — 15 Doubtful — — — — — — — — Total $ 493 $ 324 $ 74 $ 50 $ 23 $ 19 $ — $ 983 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Municipal Risk rating: Pass $ 23 $ 23 $ 8 $ 22 $ 18 $ 84 $ — $ 178 Special mention — — — — — — — — Substandard — — — — — 1 — 1 Doubtful — — — — — — — — Total $ 23 $ 23 $ 8 $ 22 $ 18 $ 85 $ — $ 179 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Agricultural Risk rating: Pass $ 30 $ 34 $ 15 $ 7 $ 3 $ 1 $ — $ 90 Special mention — — — — — — — — Substandard — 5 — — 1 — — 6 Doubtful — — — — — — — — Total $ 30 $ 39 $ 15 $ 7 $ 4 $ 1 $ — $ 96 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Construction & Development Risk rating: Pass $ 220 $ 237 $ 39 $ 18 $ 9 $ 17 $ — $ 540 Special mention 1 2 — — — — — 3 Substandard 2 2 4 — — — — 8 Doubtful — — — — — — — — Total $ 223 $ 241 $ 43 $ 18 $ 9 $ 17 $ — $ 551 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Farm Risk rating: Pass $ 59 $ 53 $ 17 $ 12 $ 9 $ 31 $ — $ 181 Special mention — — — — — — — — Substandard — 2 — 1 — 1 — 4 Doubtful — — — — — — — — Total $ 59 $ 55 $ 17 $ 13 $ 9 $ 32 $ — $ 185 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Non-Owner Risk rating: Pass $ 101 $ 171 $ 104 $ 80 $ 40 $ 138 $ — $ 634 Special mention — 1 13 1 7 3 — 25 Substandard 2 — 3 — 3 7 — 15 Doubtful — — — — — — — — Total $ 103 $ 172 $ 120 $ 81 $ 50 $ 148 $ — $ 674 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Owner Occupied CRE Risk rating: Pass $ 137 $ 178 $ 129 $ 103 $ 64 $ 157 $ — $ 768 Special mention 1 2 1 1 4 1 — 10 Substandard 8 3 5 14 2 10 — 42 Doubtful — — — — — — — — Total $ 146 $ 183 $ 135 $ 118 $ 70 $ 168 $ — $ 820 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Residential Risk rating: Pass $ 266 $ 316 $ 145 $ 105 $ 84 $ 282 $ 96 $ 1,294 Special mention — 3 1 1 1 3 — 9 Substandard 2 5 3 2 2 10 1 25 Doubtful — — — — — — — — Total $ 268 $ 324 $ 149 $ 108 $ 87 $ 295 $ 97 $ 1,328 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Auto Risk rating: Pass $ 118 $ 140 $ 76 $ 26 $ 13 $ 9 $ — $ 382 Special mention — — — — — — — — Substandard — 1 1 — — — — 2 Doubtful — — — — — — — — Total $ 118 $ 141 $ 77 $ 26 $ 13 $ 9 $ — $ 384 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Non-Auto Risk rating: Pass $ 40 $ 33 $ 14 $ 5 $ 2 $ 5 $ 6 $ 105 Special mention — — — — — — — — Substandard — — — — — — — — Doubtful — — — — — — — — Total $ 40 $ 33 $ 14 $ 5 $ 2 $ 5 $ 6 $ 105 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Total Loans Risk rating: Pass $ 1,479 $ 1,501 $ 618 $ 424 $ 264 $ 743 $ 102 $ 5,131 Special mention 6 10 16 4 13 7 — 56 Substandard 18 24 18 20 8 29 1 118 Doubtful — — — — — — — — Total $ 1,503 $ 1,535 $ 652 $ 448 $ 285 $ 779 $ 103 $ 5,305 The following summarizes the Company’s internal ratings of its loans held-for-investment, December 31, 2020 2019 2018 2017 2016 Prior Revolving Total C&I Risk rating: Pass $ 874 $ 101 $ 70 $ 28 $ 10 $ 16 $ — $ 1,099 Special mention 9 2 — 1 — — — 12 Substandard 12 4 4 — — — — 20 Doubtful — — — — — — — — Total $ 895 $ 107 $ 74 $ 29 $ 10 $ 16 $ — $ 1,131 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Municipal Risk rating: Pass $ 26 $ 19 $ 29 $ 14 $ 13 $ 71 $ — $ 172 Special mention — — — — — — — — Substandard 2 — — 5 1 1 — 9 Doubtful — — — — — — — — Total $ 28 $ 19 $ 29 $ 19 $ 14 $ 72 $ — $ 181 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Agricultural Risk rating: Pass $ 57 $ 19 $ 9 $ 3 $ 1 $ — $ — $ 89 Special mention — — — — — — — — Substandard 6 — — — — — — 6 Doubtful — — — — — — — — Total $ 63 $ 19 $ 9 $ 3 $ 1 $ — $ — $ 95 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Construction & Development Risk rating: Pass $ 371 $ 97 $ 36 $ 19 $ 7 $ 9 $ — $ 539 Special mention 2 4 — — — — — 6 Substandard 4 1 — 3 — 1 — 9 Doubtful — — — — — — — — Total $ 377 $ 102 $ 36 $ 22 $ 7 $ 10 $ — $ 554 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Farm Risk rating: Pass $ 57 $ 22 $ 18 $ 11 $ 11 $ 23 $ — $ 142 Special mention — — — — — — — — Substandard 7 1 — 1 — 1 — 10 Doubtful — — — — — — — — Total $ 64 $ 23 $ 18 $ 12 $ 11 $ 24 $ — $ 152 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Non-Owner Risk rating: Pass $ 197 $ 117 $ 93 $ 44 $ 55 $ 88 $ — $ 594 Special mention 1 — 1 8 1 — — 11 Substandard — 2 — — — 11 — 13 Doubtful — — — — — — — — Total $ 198 $ 119 $ 94 $ 52 $ 56 $ 99 $ — $ 618 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Owner Occupied CRE Risk rating: Pass $ 176 $ 132 $ 105 $ 75 $ 65 $ 132 $ — $ 685 Special mention 5 5 2 4 1 1 — 18 Substandard 5 4 20 4 1 10 — 44 Doubtful — — — — — — — — Total $ 186 $ 141 $ 127 $ 83 $ 67 $ 143 $ — $ 747 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Residential Risk rating: Pass $ 373 $ 172 $ 134 $ 101 $ 101 $ 237 $ 93 $ 1,211 Special mention 3 1 1 1 1 3 — 10 Substandard 5 3 3 3 1 10 2 27 Doubtful — — — — — — — — Total $ 381 $ 176 $ 138 $ 105 $ 103 $ 250 $ 95 $ 1,248 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Auto Risk rating: Pass $ 177 $ 104 $ 39 $ 21 $ 9 $ 2 $ — $ 352 Special mention — — — — — — — — Substandard 1 1 — — — — — 2 Doubtful — — — — — — — — Total $ 178 $ 105 $ 39 $ 21 $ 9 $ 2 $ — $ 354 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Non-Auto Risk rating: Pass $ 48 $ 21 $ 7 $ 4 $ 1 $ 2 $ 7 $ 90 Special mention — — — — — — — — Substandard — — — — — 1 — 1 Doubtful — — — — — — — — Total $ 48 $ 21 $ 7 $ 4 $ 1 $ 3 $ 7 $ 91 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Total Loans Risk rating: Pass $ 2,356 $ 804 $ 540 $ 320 $ 273 $ 580 $ 100 $ 4,973 Special mention 20 12 4 14 3 4 — 57 Substandard 42 16 27 16 3 35 2 141 Doubtful — — — — — — — — Total $ 2,418 $ 832 $ 571 $ 350 $ 279 $ 619 $ 102 $ 5,171 The following tables summarize the Company’s internal ratings of its loans held-for-investment, June 30, 2020 Pass Special Substandard Doubtful Total Commercial $ 1,465 $ 9 $ 35 $ — $ 1,509 Agricultural 91 5 2 — 98 Real Estate 3,087 50 98 — 3,235 Consumer 409 — 2 — 411 Total $ 5,052 $ 64 $ 137 $ — $ 5,253 The Company’s past due loans are as follows (in thousands): June 30, 2021 15-59 60-89 Greater Total Past Current Total Loans 90 Days Commercial: C&I $ 3,432 $ 707 $ 230 $ 4,369 $ 978,734 $ 983,103 $ — Municipal 1,656 — — 1,656 177,700 179,356 — Total Commercial 5,088 707 230 6,025 1,156,434 1,162,459 — Agricultural 193 10 35 238 94,974 95,212 — Real Estate: Construction & Development 1,973 — 162 2,135 548,793 550,928 — Farm 1,138 — — 1,138 184,150 185,288 — Non-Owner 896 161 — 1,057 672,551 673,608 — Owner Occupied CRE 97 821 — 918 819,137 820,055 — Residential 5,946 373 100 6,419 1,322,055 1,328,474 — Total Real Estate 10,050 1,355 262 11,667 3,546,686 3,558,353 — Consumer: Auto 330 55 25 410 383,354 383,764 — Non-Auto 44 11 — 55 104,759 104,814 — Total Consumer 374 66 25 465 488,113 488,578 — Total $ 15,705 $ 2,138 $ 552 $ 18,395 $ 5,286,207 $ 5,304,602 $ — December 31, 2020 15-59 60-89 Greater Total Past Current Total Loans 90 Days Commercial: C&I $ 3,647 $ 406 $ 576 $ 4,629 $ 1,126,753 $ 1,131,382 $ 21 Municipal — — — — 181,325 181,325 — Total Commercial 3,647 406 576 4,629 1,308,078 1,312,707 21 Agricultural 193 95 — 288 94,576 94,864 — Real Estate: Construction & Development 4,775 44 — 4,819 549,140 553,959 — Farm 708 — — 708 151,529 152,237 — Non-Owner 613 — — 613 617,073 617,686 — Owner Occupied CRE 1,393 322 133 1,848 745,126 746,974 — Residential 8,072 18 275 8,365 1,240,044 1,248,409 33 Total Real Estate 15,561 384 408 16,353 3,302,912 3,319,265 33 Consumer: Auto 551 158 75 784 352,811 353,595 59 Non-Auto 214 24 — 238 90,364 90,602 — Total Consumer 765 182 75 1,022 443,175 444,197 59 Total $ 20,166 $ 1,067 $ 1,059 $ 22,292 $ 5,148,741 $ 5,171,033 $ 113 June 30, 2020 15-59 60-89 Greater Total Current Total Loans 90 Days Commercial $ 4,563 $ 474 $ 129 $ 5,166 $ 1,504,288 $ 1,509,454 $ — Agricultural 1,080 15 — 1,095 96,353 97,448 — Real Estate 13,678 110 726 14,514 3,220,694 3,235,208 — Consumer 410 83 105 598 410,359 410,957 92 Total $ 19,731 $ 682 $ 960 $ 21,373 $ 5,231,694 $ 5,253,067 $ 92 * The Company monitors commercial, agricultural and real estate loans after such loans are 15 days past due. Consumer loans are monitored after such loans are 30 days past due. The restructuring of a loan is considered a “troubled debt restructuring” if both the borrower is experiencing financial difficulties and the creditor has granted a concession. Concessions may include interest rate reductions or below market interest rates, principal forgiveness, restructuring amortization schedules, reductions in collateral and other actions intended to minimize potential losses. The Company’s loans that were modified and considered troubled debt restructurings are as follows (in thousands): Three-Months Ended June 30, 2021 Six-Months Pre- Modification Post- Modification Pre- Modification Post- Modification Recorded Recorded Recorded Recorded Number Investment Investment Number Investment Investment Commercial: C&I 2 $ 212 $ 212 4 $ 361 $ 361 Municipal — — — — — — Total Commercial 2 212 212 4 361 361 Agricultural 1 68 68 1 68 68 Real Estate: Construction & Development 1 200 200 1 200 200 Farm — — — — — — Non-Owner — — — — — — Owner Occupied CRE 2 548 548 3 1,047 1,047 Residential 1 245 245 3 443 443 Total Real Estate 4 993 993 7 1,690 1,690 Consumer: Auto 1 31 31 1 31 31 Non-Auto — — — — — — Total Consumer 1 31 31 1 31 31 Total 8 $ 1,304 $ 1,304 13 $ 2,150 $ 2,150 Three-Months Ended June 30, 2020 Six-Months Pre- Modification Post- Pre- Modification Post- Recorded Recorded Recorded Recorded Number Investment Investment Number Investment Investment Commercial 4 $ 196 $ 196 9 $ 484 $ 484 Agricultural — — — 1 134 134 Real Estate 1 123 123 1 123 123 Consumer — — — 1 14 14 Total 5 $ 319 $ 319 12 $ 755 $ 755 The balances below provide information as to how the loans were modified as troubled debt restructured loans (in thousands): Three-Months Ended June 30, 2021 Six-Months Adjusted Combined Adjusted Combined Interest Maturity Rate and Interest Maturity Rate and Rate Extended Maturity Rate Extended Maturity Commercial: C&I $ — $ 212 $ — $ — $ 212 $ 149 Municipal — — — — — — Total Commercial — 212 — — 212 149 Agricultural — 68 — — 68 — Real Estate: Construction & Development — 200 — — 200 — Farm — — — — — — Non-Owner — — — — — — Owner Occupied CRE — — 548 — — 1,047 Residential — 245 — — 245 198 Total Real Estate — 445 548 — 445 1,245 Consumer: Auto — — 31 — — 31 Non-Auto — — — — — — Total Consumer — — 31 — — 31 Total $ — $ 725 $ 579 $ — $ 725 $ 1,425 Three-Months Ended June 30, 2020 Six-Months Adjusted Combined Adjusted Combined Interest Maturity Rate and Interest Maturity Rate and Rate Extended Maturity Rate Extended Maturity Commercial $ — $ — $ 196 $ — $ 260 $ 224 Agricultural — — — — 134 — Real Estate — — 123 — — 123 Consumer — — — — 14 — Total $ — $ — $ 319 $ — $ 408 $ 347 During the three and six-months As of June 30, 2021, the Company has no commitments to lend additional funds to loan customers whose terms have been modified in troubled debt restructurings.

Loans Held for Sale

Loans Held for Sale	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Loans Held for Sale	Note 4 - Loans Held-for-Sale Loans held-for-sale These loans, which are sold on a servicing released basis, are valued using a market approach by utilizing either: (i) the fair value of the securities backed by similar mortgage loans, adjusted for certain factors to approximate the fair value of a whole mortgage loan, including the value attributable to mortgage servicing and credit risk, (ii) current commitments to purchase loans or (iii) recent observable market trades for similar loans, adjusted for credit risk and other individual loan characteristics. As these prices are derived from market observable inputs, the Company classifies these valuations as Level 2 in the fair value disclosures (see Note 9). Interest income on mortgage loans held-for-sale The Company originates certain mortgage loans for sale in the secondary market. The mortgage loan sales contracts contain indemnification clauses should the loans default, generally in the first three to six months, or if documentation is determined not to be in compliance with regulations. The Company’s historic losses as a result of these indemnities have been insignificant.

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Note 5 - Derivative Financial Instruments The Company enters into interest rate lock commitments (“IRLCs”) with customers to originate residential mortgage loans at a specific interest rate that are ultimately sold in the secondary market. These commitments, which contain fixed expiration dates, offer the borrower an interest rate guarantee provided the loan meets underwriting guidelines and closes within the timeframe established by the Company. The Company purchases forward mortgage-backed securities contracts to manage the changes in fair value associated with changes in interest rates related to a portion of the IRLCs. These instruments are typically entered into at the time the IRLC is made in the aggregate. These financial instruments are not designated as hedging instruments for accounting purposes. All derivatives are carried at fair value in either other assets or other liabilities, through earnings in the statement of earnings. The fair values of IRLCs are based on current secondary market prices for underlying loans and estimated servicing value with similar coupons, maturity and credit quality, subject to the anticipated loan funding probability (pull-through rate) net of estimated costs to originate the loan. The fair value of IRLCs is subject to change primarily due to changes in interest rates and the estimated pull-through rate. These commitments are classified as Level 2 in the fair value disclosures (see Note 9), as the valuations are based on observable market inputs. Forward mortgage-backed securities contracts are exchange-traded or traded within highly active dealer markets. In order to determine the fair value of these instruments, the Company utilizes the exchange price or dealer market price for the particular derivative contract and these instruments are therefore classified as Level 2 in the fair value disclosures (see Note 9). The estimated fair values are subject to change primarily due to changes in interest rates. The impact of these forward contracts is included in gain on sale and fees on mortgage loans in the statement of earnings. The following table provides the outstanding notional balances and fair values of outstanding derivative positions (in thousands): June 30, 2021: Outstanding Asset Liability IRLCs $ 143,879 $ 2,670 $ — Forward mortgage-backed securities trades 165,000 — 376 June 30, 2020: Outstanding Asset Liability IRLCs $ 190,431 $ 5,037 $ — Forward mortgage-backed securities trades 201,500 — 1,099 December 31, 2020: Outstanding Asset Liability IRLCs $ 202,906 $ 4,618 $ — Forward mortgage-backed securities trades 198,000 — 1,560

Borrowings

Borrowings	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Borrowings	Note 6 – Borrowings Borrowings consisted of the following (dollars in thousands): June 30, December 31, 2021 2020 2020 Securities sold under agreements with customers to repurchase $ 531,469 $ 444,249 $ 412,743 Federal funds purchased 18,500 4,975 17,350 Advances from Federal Home Loan Bank of Dallas — — — Total $ 549,969 $ 449,224 $ 430,093 Securities sold under repurchase agreements are generally with significant customers of the Company that require short-term liquidity for their funds for which the Company pledges certain securities that have a fair value equal to at least the amount of the borrowings. The agreements mature daily and therefore the risk arising from a decline in the fair value of the collateral pledged is minimal. The securities pledged are mortgage-backed securities. These agreements do not include “right of set-off” The Company renewed its loan agreement, effective June 30, 2021, with Frost Bank. Under the loan agreement, as renewed and amended, we are permitted to draw up to $25,000,000 on a revolving line of credit. There was no outstanding balance under the line of credit as of June 30, 2021 and 2020, or December 31, 2020.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Note 7 - Income Taxes Income tax expense was $11,075,000 for the second quarter of 2021 as compared to $10,663,000 for the same period in 2020. The Company’s effective tax rates on pretax income were 16.42% and 16.63% for the second quarters of 2021 and 2020, respectively. Income tax expense was $22,129,000 for the six months ended June 30, 2021 as compared to 17,898,000 for the same period in 2020. The Company’s effective tax rates on pretax income were 16.34% and 16.48% for the six-months

Stock Option Plan and Restricte

Stock Option Plan and Restricted Stock Plan	6 Months Ended
	Jun. 30, 2021
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plan and Restricted Stock Plan	Note 8 - Stock Option Plan and Restricted Stock Plan Omnibus Stock and Incentive Plan On April 27, 2021, the Company’s shareholders approved a new 2021 Omnibus Stock and Incentive Plan (“2021 Plan”) and reserved 2,500,000 shares of the Company’s common stock for issuance under this plan. At June 30, 2021, the Company had 2,487,890 shares of stock remaining for issuance under the plan. The 2021 Plan supersedes all prior stock option and restricted stock plans with previously reserved shares cancelled. Stock Option Plans Prior to the approval of the 2021 Plan, the 2012 Incentive Stock Option Plan (the “2012 Plan”) provided for the granting of options to employees of the Company at prices not less than market value at the date of grant. On April 27, 2021, the 2012 Plan was superseded by the new 2021 Plan and all previous reserved shares were cancelled and the 2021 Plan reserved 2,500,000 shares for future issuances. The 2012 Plan provided that options granted vest and are exercisable after two years from the date of grant and vest at a rate of 20% each year thereafter and have a 10-year six-months Shares Weighted- Outstanding, December 31, 2020 1,833,057 $ 20.85 Granted — — Exercised (165,371 ) 15.89 Cancelled (17,600 ) 25.61 Outstanding, June 30, 2021 1,650,086 21.29 Exercisable, June 30, 2021 938,436 $ 19.04 The options outstanding at June 30, 2021 had exercise prices ranging between $7.87 and $34.55. Stock options have been adjusted retroactively for the effects of stock dividends and splits. The Company grants incentive stock options for a fixed number of shares with an exercise price equal to the fair value of the shares at the date of grant to employees. The Company recorded stock option expense totaling $372,000 and $349,000 for the three-month periods ended June 30, 2021 and 2020, respectively. The Company recorded stock option expense totaling $691,000 and $689,000 for the six months ended June 30, 2021 and 2020, respectively. As of June 30, 2021, there was $3,374,000 of total unrecognized compensation cost related to unvested share-based compensation arrangements related to stock options granted under the Company’s stock option plans. That cost is expected to be recognized over a weighted-average period of 1.69 years. The total fair value of shares vested during the six-months Restricted Stock Plan On April 28, 2015, shareholders of the Company approved the 2015 Restricted Stock Plan (the “2015 Plan”) for selected employees, officers, non-employee The following table summarizes information about vested and unvested restricted stock. For the six-months 2021 2020 Restricted Weighted Restricted Weighted Balance at beginning of period 95,888 $ 29.89 105,309 $ 29.93 Grants 12,110 49.58 32,149 28.55 Vesting (31,081 ) 28.42 (30,276 ) 30.27 Forfeited/expired (1,027 ) 34.55 (239 ) 29.70 Balance at end of period 75,890 $ 33.57 106,943 $ 29.42 The total fair value of restricted stock vested for the six-months The Company recorded restricted stock expense for employees of $289,000 and $322,000, respectively, for the three-months ended June 30, 2021 and 2020, respectively. The Company recorded restricted stock expense for employees of $579,000 and $597,000 for the six-month six-months As of June 30, 2021, and 2020, there were $1,845,000 and $2,441,000, respectively, of total unrecognized compensation cost related to unvested restricted stock which is expected to be recognized over a weighted-average period of 1.33 years and 1.76 years, respectively. At June 30, 2021 and 2020, and December 31, 2020, there was $59,000, $55,000 and $49,000, respectively, accrued in other liabilities related to dividends declared to be paid upon vesting.

Fair Value Disclosures

Fair Value Disclosures	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Disclosures	Note 9 - Fair Value Disclosures The authoritative accounting guidance for fair value measurements defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. A fair value measurement assumes that the transaction to sell the asset or transfer the liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability. The price in the principal (or most advantageous) market used to measure the fair value of the asset or liability shall not be adjusted for transaction costs. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for marketing activities that are usual and customary for transactions involving such assets and liabilities; it is not a forced transaction. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. The authoritative accounting guidance requires the use of valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable assets and liabilities. The income approach uses valuation techniques to convert future amounts, such as cash flows or earnings, to a single present amount on a discounted basis. The cost approach is based on the amount that currently would be required to replace the service capacity of an asset (replacement costs). Valuation techniques should be consistently applied. Inputs to valuation techniques refer to the assumptions that market participants would use in pricing the asset or liability. Inputs may be observable, meaning those that reflect the assumptions market participants would use in pricing the asset or liability developed based on market data obtained from independent sources, or unobservable, meaning those that reflect the reporting entity’s own assumptions about the assumptions market participants would use in pricing the asset or liability developed based on the best information available in the circumstances. In that regard, the authoritative guidance establishes a fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The fair value hierarchy is as follows: • Level 1 Inputs – Unadjusted quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. • Level 2 Inputs – Inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. These include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (for example, interest rates, volatilities, prepayment speeds, loss severities, credit risks and default rates) or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3 Inputs – Significant unobservable inputs that reflect an entity’s own assumptions that market participants would use in pricing the assets or liabilities. A description of the valuation methodologies used for assets and liabilities measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, fair value is based upon internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be made to ensure that financial instruments are recorded at fair value. While management believes the Company’s valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Securities classified as available-for-sale See Notes 4 and 5 related to the determination of fair value for loans held-for-sale, There were no transfers between Level 2 and Level 3 during the three and six-months The following table summarizes the Company’s available-for-sale held-for-sale, June 30, 2021 Level 1 Level 2 Level 3 Total Fair Available-for-sale Obligations of states and political subdivisions $ — $ 2,615,087 $ — $ 2,615,087 Corporate bonds — 33,318 — 33,318 Residential mortgage-backed securities — 2,504,186 — 2,504,186 Commercial mortgage-backed securities — 420,968 — 420,968 Other securities 4,489 — — 4,489 Total $ 4,489 $ 5,573,559 $ — $ 5,578,048 Loans held-for-sale $ — $ 56,257 $ — $ 56,257 IRLCs $ — $ 2,670 $ — $ 2,670 Forward mortgage-backed securities trades liability $ — $ (376 ) $ — $ (376 ) June 30, 2020 Level 1 Level 2 Level 3 Total Fair Available-for-sale U.S. Treasury securities $ 10,122 $ — $ — $ 10,122 Obligations of states and political subdivisions — 1,950,279 — 1,950,279 Residential mortgage-backed securities — 1,571,673 — 1,571,673 Commercial mortgage-backed securities — 582,220 — 582,220 Other securities 4,569 — — 4,569 Total $ 14,691 $ 4,104,172 $ — $ 4,118,863 Loans held-for-sale $ — $ 63,293 $ — $ 63,293 IRLCs $ — $ 5,037 $ — $ 5,037 Forward mortgage-backed securities trades liability $ — $ (1,099 ) $ — $ (1,099 ) December 31, 2020 Level 1 Level 2 Level 3 Total Fair Available-for-sale Obligations of state and political subdivisions $ — $ 2,426,876 $ — $ 2,426,876 Residential mortgage-backed securities — 1,472,280 — 1,472,280 Commercial mortgage-backed securities — 489,316 — 489,316 Other securities 4,557 — — 4,557 Total $ 4,557 $ 4,388,472 $ — $ 4,393,029 Loans held-for-sale $ — $ 79,585 $ — $ 79,585 IRLCs $ — $ 4,618 $ — $ 4,618 Forward mortgage-backed securities trades liability $ — $ (1,560 ) $ — $ (1,560 ) The following table summarizes the Company’s loans held-for-sale June 30, December 31, 2021 2020 2020 Unpaid principal balance on loans held-for-sale $ 54,542 $ 60,432 $ 76,602 Net unrealized gains on loans held-for-sale 1,715 2,861 2,983 Loans held-for-sale $ 56,257 $ 63,293 $ 79,585 The following table summarizes the Company’s gains on sale and fees of mortgage loans for the three and six-months ended June 30, 2021 and 2020 (in thousand): Three-Months ended Six-Months 2021 2020 2021 2020 Realized gain on sale and fees on mortgage loans* $ 9,465 $ 7,637 $ 20,195 $ 10,103 Change in fair value on loans held-for-sale 2,008 3,937 (3,193 ) 6,292 Change in forward mortgage-backed securities trades (3,182 ) 2,102 1,183 (946 ) Total gain on sale of mortgage loans $ 8,291 $ 13,676 $ 18,185 $ 15,449 * This includes gains on loans held-for-sale No residential mortgage loans held-for-sale held-for-sale six-months Certain non-financial non-financial non-financial Non-financial non-recurring six-months re-measured Re-evaluation re-measured six-months At June 30, 2021 and 2020, and December 31, 2020, other real estate owned totaled $283,000, $202,000 and $119,000, respectively. The Company is required under current authoritative accounting guidance to disclose the estimated fair value of their financial instrument assets and liabilities including those subject to the requirements discussed above. For the Company, as for most financial institutions, substantially all of its assets and liabilities are considered financial instruments. Many of the Company’s financial instruments, however, lack an available trading market as characterized by a willing buyer and willing seller engaging in an exchange transaction. The estimated fair value amounts of financial instruments have been determined by the Company using available market information and appropriate valuation methodologies. However, considerable judgment is required to interpret data to develop the estimates of fair value. Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company could realize in a current market exchange. The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts. In addition, reasonable comparability between financial institutions may not be likely due to the wide range of permitted valuation techniques and numerous estimates that must be made given the absence of active secondary markets for many of the financial instruments. This lack of uniform valuation methodologies also introduces a greater degree of subjectivity to these estimated fair values. Cash and due from banks, federal funds sold, interest-bearing deposits and time deposits in banks and accrued interest receivable and payable are liquid in nature and considered Levels 1 or 2 of the fair value hierarchy. Financial instruments with stated maturities have been valued using a present value discounted cash flow with a discount rate approximating current market for similar assets and liabilities and are considered Levels 2 and 3 of the fair value hierarchy. Financial instrument liabilities with no stated maturities have an estimated fair value equal to both the amount payable on demand and the carrying value and are considered Level 1 of the fair value hierarchy. The carrying value and the estimated fair value of the Company’s contractual off-balance-sheet The estimated fair values and carrying values of all financial instruments under current authoritative guidance were as follows (in thousands). June 30, December 31, 2021 2020 2020 Carrying Estimated Carrying Estimated Carrying Estimated Fair Value Cash and due from banks $ 190,061 $ 190,061 $ 188,373 $ 188,373 $ 211,113 $ 211,113 Level 1 Interest-bearing demand deposits in banks 654,531 654,531 196,426 196,426 517,971 517,971 Level 1 Available-for-sale 5,578,048 5,578,048 4,118,863 4,118,863 4,393,029 4,393,029 Levels 1 Loans held-for-investment, 5,242,464 5,273,264 5,184,120 5,174,126 5,104,499 5,109,885 Level 3 Loans held-for-sale 61,802 61,969 66,370 66,630 83,969 84,233 Level 2 Accrued interest receivable 54,128 54,128 45,801 45,801 53,433 53,433 Level 2 Deposits with stated maturities 470,481 471,857 466,122 468,819 475,542 477,218 Level 2 Deposits with no stated maturities 9,311,213 9,311,213 7,691,520 7,691,520 8,200,275 8,200,275 Level 1 Borrowings 549,969 549,969 449,224 449,224 430,093 430,093 Level 2 Accrued interest payable 316 316 541 541 377 377 Level 2 IRLCs 2,670 2,670 5,037 5,037 4,618 4,618 Level 2 Forward mortgage-backed securities trades liability (376 ) (376 ) (1,099 ) (1,099 ) (1,560 ) (1,560 ) Level 2

Acquisition

Acquisition	6 Months Ended
	Jun. 30, 2021
Business Combinations [Abstract]
Acquisition	Note 10 – Acquisition On September 19, 2019, we entered into an agreement and plan of reorganization to acquire TB&T Bancshares, Inc. and its wholly-owned bank subsidiary, The Bank & Trust of Bryan/College Station, Texas. On January 1, 2020, the transaction was completed. Pursuant to the agreement, we issued 6,275,574 shares of the Company’s common stock in exchange for all of the outstanding shares of TB&T Bancshares, Inc. In addition, TBT Bancshares, Inc. made a $1,920,000 special dividend to its shareholders prior to closing of the transaction. At closing, a wholly-owned subsidiary of the Company merged into TB&T Bancshares, Inc. and immediately thereafter TB&T Bancshares, Inc. was merged into the Company and The Bank & Trust of Bryan/College Station, Texas, was merged into First Financial Bank, N.A., a wholly-owned subsidiary of the Company. The primary purpose of the acquisition was to expand the Company’s market share near the Houston market. Factors that contributed to a purchase price resulting in goodwill include its record of earnings, strong management and board of directors, strong local economic environment and opportunity for growth. The results of operations from this acquisition are included in the consolidated earnings of the Company commencing January 1, 2020. The following table presents the final amounts recorded on the consolidated balance sheet on the acquisition date (dollars in thousands): Fair value of consideration paid: Common stock issued (6,275,574 shares) $ 220,273 Fair value of identifiable assets acquired: Cash and cash equivalents $ 61,028 Securities available-for-sale 93,967 Loans 447,702 Identifiable intangible assets 4,798 Other assets 25,377 Total identifiable assets acquired $ 632,872 Fair value of liabilities assumed: Deposits $ 549,125 Other liabilities 5,397 Total liabilities assumed $ 554,522 Fair value of net identifiable assets acquired 78,350 Goodwill resulting from acquisition $ 141,923 Goodwill recorded in the acquisition was accounted for in accordance with the authoritative business combination guidance. Accordingly, goodwill will not be amortized but will be tested for impairment annually. The goodwill recorded is not deductible for federal income tax purposes. The fair value of total loans acquired was $447,702,000 at acquisition compared to contractual amounts of $455,181,000.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations First Financial Bankshares, Inc. (a Texas corporation) (“Bankshares”, “Company,” “we” or “us”) is a financial holding company which owns all of the capital stock of one bank with 78 locations located in Texas as of June 30, 2021. The Company’s subsidiary bank is First Financial Bank, N.A. The Company’s primary source of revenue is providing loans and banking services to consumers and commercial customers in the market area in which First Financial Bank, N.A. is located. In addition, the Company also owns First Financial Trust & Asset Management Company, N.A., First Financial Insurance Agency, Inc. and First Technology Services, Inc.
Basis of Presentation	Basis of Presentation A summary of significant accounting policies of the Company and its subsidiaries applied in the preparation of the accompanying consolidated financial statements follows. The accounting principles followed by the Company and the methods of applying them are in conformity with both United States generally accepted accounting principles (“GAAP”) and prevailing practices of the banking industry. The Company evaluated subsequent events for potential recognition through the date the consolidated financial statements were issued.
Use of Estimates in Preparation of Financial Statements	Use of Estimates in Preparation of Financial Statements The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The Company’s significant estimates include its allowance for credit losses and its valuation of financial instruments.
Consolidation	Consolidation The accompanying consolidated financial statements include the accounts of the Company and its subsidiaries, all of which are wholly-owned. All significant intercompany accounts and transactions have been eliminated.
Stock Repurchase	Stock Repurchase On March 12, 2020, the Company’s Board of Directors authorized the repurchase of up to 4,000,000 common shares through September 30, 2021. On July 27, 2021, the Company’s Board of Directors renewed the prior authorization and authorized the repurchase of up to 5,000,000 common shares through July 31, 2023. The stock repurchase plan authorizes management to repurchase and retire the stock at such time as repurchases and retirements are considered beneficial to the Company and stockholders. Any repurchase of stock will be made through the open market, block trades or in privately negotiated transactions in accordance with applicable laws and regulations. Under the repurchase plan, there is no minimum number of shares that the Company is required to repurchase. Through June 30, 2021, 324,802 shares were repurchased and retired (all during the months of March and April 2020) totaling $8,008,000 under this repurchase plan.
Acquisition	Acquisition On January 1, 2020, the Company acquired 100% of the outstanding capital stock of TB&T Bancshares, Inc. through the merger of a wholly-owned subsidiary with and into TB&T Bancshares, Inc. Following such merger, TB&T Bancshares, Inc. and its wholly-owned subsidiary, The Bank & Trust of Bryan/College Station, Texas were merged into the Company and First Financial Bank, N.A., respectively. The results of operations of TB&T Bancshares, Inc. subsequent to the acquisition date, are included in the consolidated earnings of the Company. See Note 10 for additional information.
Adoption of New Accounting Standards	Adoption of New Accounting Standards On January 1, 2020, ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments held-to-maturity off-balance-sheet available-for-sale available-for-sale On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was signed by the President of the United States that included an option for entities to delay the implementation of ASC 326 until the earlier of the termination date of the national emergency declaration by the President or December 31, 2020. Under this option, the Company elected to delay its implementation of CECL and calculated and recorded the provision for credit losses through the nine-months ended September 30, 2020 under the incurred loss model. At December 31, 2020, the Company elected to adopt ASC 326, effective as of January 1, 2020, through a transition charge to retained earnings of $589,000 ($466,000 net of applicable income taxes). This transition adjustment was comprised of a decrease of $619,000 in allowance for credit losses and an increase of $1,208,000 in the reserve for unfunded commitments. With the adoption of ASC 326, we revised certain accounting policies and implemented certain accounting policy elections which are described below. For the 2020 interim reporting periods, the allowance for credit losses were based on the incurred loss methodology in accordance with accounting policies disclosed in Note 1 of the Consolidated Financial Statements included in the Company’s 2019 Form 10-K. The Company adopted ASC 326 using the modified retrospective method for all financial assets measured at amortized cost, net investment in leases and OBS credit exposures. The Company adopted ASC 326 using the prospective transition approach for securities for which other-than-temporary impairment had been recognized prior to January 1, 2020. As a result, the amortized cost basis remains the same before and after the effective date of ASC 326. The effective interest rate on these debt securities was not changed. The Company adopted ASC 326 using the prospective transition approach for financial assets purchased with credit deterioration (“PCD”) that were previously classified as purchased credit impaired (“PCI”) and accounted for under ASC 310-30.
Other Recently Issued and Effective Authoritative Accounting Guidance	Other Recently Issued and Effective Authoritative Accounting Guidance ASU 2017-04, 2017-04 2017-04 ASU 2018-13, “ Fair Value Measurement (Topic 820). – Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. ” 2018-13 2018-13 2018-13 ASU 2019-12, 2019-12, step-up 2019-12 2019-12 ASU 2020-04, 2020-04 2020-04 2020-04 2020-04 ASU 2021-01, 2021-01 2021-01 2021-01 2021-01
Investment Securities	Investment Securities Management classifies debt securities as held-to-maturity, available-for-sale, held-to-maturity held-to-maturity available-for-sale Interest income includes amortization of purchase premiums and discounts over the period to maturity using a level-yield method, except for premiums on callable securities, which are amortized to their earliest call date. Realized gains and losses are recorded on the sale of securities in noninterest income. The Company has made a policy election to exclude accrued interest from the amortized cost basis of securities and report accrued interest separately in other assets on the consolidated balance sheets. A security is placed on non-accrual non-accrual six-months The Company records its available-for-sale The Company’s investment portfolio currently consists of obligations of state and political subdivisions, mortgage pass-through securities, corporate bonds and general obligation or revenue based municipal bonds. Pricing for such securities is generally readily available and transparent in the market. The Company utilizes independent third-party pricing services to value its investment securities, which the Company reviews as well as the underlying pricing methodologies for reasonableness and to ensure such prices are aligned with pricing matrices. The Company validates prices supplied by the independent pricing services by comparison to prices obtained from other third-party sources on a quarterly basis.
Allowance for Credit Losses – Available-for-Sale Securities	Allowance for Credit Losses – Available-for-Sale For available-for-sale charged-off available-for-sale Management has made the accounting policy election to exclude accrued interest receivable on available-for-sale Available-for-sale charged-off
Allowance for Credit Losses – Held-to-Maturity Securities	Allowance for Credit Losses – Held-to-Maturity The allowance for credit losses on held-to-maturity held-to-maturity Held-to-maturity charged-off held-to-maturity held-to-maturity At June 30, 2021, 2020 and December 31, 2020, the Company held no securities that were classified as held-to-maturity.
Loans Held-for-Investment	Loans Held-for-Investment Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff are reported at amortized cost, net of the allowance for credit losses. Amortized cost is the principal balance outstanding, net of purchase premiums and discounts, fair value hedge accounting adjustments, deferred loan fees and costs. The Company has made a policy election to exclude accrued interest from the amortized cost basis of loans and report accrued interest separately from the related loan balance in other assets on the condensed consolidated balance sheets. Interest on loans is calculated by using the simple interest method on daily balances of the principal amounts outstanding. The Company defers and amortizes net loan origination fees and costs as an adjustment to yield. Loans are considered past due if the required principal and interest payments have not been received as of the date such payments were due. Loans are placed on non-accrual non-accrual non-accrual non-accrual Prior to the adoption of ASC 326, loans were reported as impaired when, based on then current information and events, it was probable we would be unable to collect all amounts due in accordance with the original contractual terms of the loan agreement, including scheduled principal and interest payments. Impairment was evaluated in total for smaller-balance loans of a similar nature and on an individual loan basis for other loans. If a loan was impaired, a specific valuation allowance was allocated, if necessary, so that the loan was reported net, at the present value of estimated future cash flows using the loan’s existing rate or at the fair value of collateral if repayment was expected solely from the collateral. Interest payments on impaired loans were typically applied to principal unless collectability of the principal amount was reasonably assured, in which case interest was recognized on a cash basis. Impaired loans, or portions thereof, were charged off when deemed uncollectible. Further information regarding our accounting policies related to past due loans, non-accrual
Acquired Loans	Acquired Loans Loans acquired in connection with acquisitions are recorded at their acquisition-date fair value. The allowance for credit losses related to the acquired loan portfolio is not carried over. Acquired loans are classified into two categories based on the credit risk characteristics of the underlying borrowers as either purchased credit deteriorated (“PCD”) loans, or loans with no evidence of credit deterioration (“non-PCD”). PCD loans are defined as a loan or pool of loans that have experienced more-than-insignificant credit deterioration since the origination date. The Company uses a combination of individual and pooled review approaches to determine if acquired loans are PCD. At acquisition, the Company considers a number of factors to determine if an acquired loan or pool of loans has experienced more-than-insignificant credit deterioration. The initial allowance related to PCD loans that share similar risk characteristics is established using a pooled approach. The Company uses either a discounted cash flow or weighted average remaining life method to determine the required level of the allowance. PCD loans that were classified as non-accrual For PCD loans, an initial allowance is established on the acquisition date and combined with the fair value of the loan to arrive at acquisition date amortized cost. Subsequent to the acquisition date, the initial allowance for credit losses on PCD loans will increase or decrease based on future evaluations, with changes recognized in the provision for credit losses. Non-PCD Determining the fair value of the acquired loans involves estimating the principal and interest payment cash flows expected to be collected on the loans and discounting those cash flows at a market rate of interest. Management considers a number of factors in evaluating the acquisition-date fair value including the remaining life, interest rate profile, market interest rate environment, payment schedules, risk ratings, probability of default and loss given default, and estimated prepayment rates. For PCD loans, the non-credit non-credit non-PCD Prior to the adoption of ASC 326, loans acquired in a business combination that had evidence of credit impairment and for which it was probable, at acquisition, that the Company would be unable to collect all contractually required payments receivable were considered PCI. PCI loans were accounted for individually or aggregated into pools of loans based on common risk characteristics such as credit grade, loan type, and date of origination.
Allowance for Credit Losses - Loans	Allowance for Credit Losses - Loans The allowance for credit losses (“allowance” or “ACL”) is a contra-asset valuation account, calculated in accordance with ASC 326, that is deducted from the amortized cost basis of loans. The ACL represents an amount which, in management’s judgement, is adequate to absorb the lifetime expected credit losses that may be experienced on outstanding loans at the balance sheet date based on the evaluation of the size and current risk characteristics of the loan portfolio, past events, current conditions, reasonable and supportable forecasts of future economic conditions and prepayment experience. The allowance for credit losses is measured and recorded upon the initial recognition of a financial asset. Determination of the adequacy of the allowance is inherently complex and requires the use of significant and highly subjective estimates. Loans are charged-off charged-off charged-off. The Company’s methodology for estimating the allowance includes: (1) a collective quantified reserve that reflects the Company’s historical default and loss experience adjusted for expected economic conditions throughout a reasonable and supportable forecast period, including the Company’s expected prepayment and curtailment rates; (2) collective qualitative factors that consider concentrations of the loan portfolio, expected changes to the economic forecasts, notable changes in a loan segments economic environment, large relationships, early delinquencies, and factors related to credit administrations, including, among others, loan-to-value In calculating the allowance for credit losses, most loans are segmented into pools based upon similar characteristics and risk profiles. Common characteristics and risk profiles include the type/purpose of loan, underlying collateral, geographical similarity and historical/expected credit loss patterns. In developing these loan pools for the purposes of modeling expected credit losses, we also analyzed the degree of correlation in how loans within each portfolio respond when subjected to varying economic conditions and scenarios as well as other portfolio stress factors. For modeling purposes, our loan portfolio segments include Commercial and Industrial (“C&I”), Municipal, Agricultural, Construction and Development, Farm, Non-Owner Non-Auto. The Company applies two methodologies to estimate the allowance on its pooled portfolio segments; discounted cash flows method and weighted average remaining life method. Allowance estimates on the following portfolio segments are calculated using the discounted cash flows method: C&I, Municipal, Construction and Development, Farm, Non-Owner Non-Auto. one-year In some cases, management may determine that an individual loan exhibits unique risk characteristics which differentiate the loan from other loans within our loan pools. In such cases, the loans are evaluated for expected credit losses on an individual basis and excluded from the collective evaluation. Specific allocations of the allowance for credit losses are determined by analyzing the borrower’s ability to repay amounts owed, collateral deficiencies, the relative risk rating of the loan and economic conditions affecting the borrower’s industry, among other things. A loan is considered to be collateral dependent when, based upon management’s assessment, the borrower is experiencing financial difficulty and repayment is expected to be provided substantially through the sale of the collateral. In such cases, expected credit losses are based on the fair value of the collateral at the measurement date, adjusted for estimated selling costs if satisfaction of the loan depends on the sale of the collateral. We reevaluate the fair value of collateral supporting collateral dependent loans on an ongoing basis. Management qualitatively adjusts model results for risk factors that are not considered within our modeling processes but are nonetheless relevant in assessing the expected credit losses within our loan pools. These qualitative factor (“Q-Factor”) Q-Factor non-accrual non-collateral Management believes it uses relevant information available to make determinations about the allowance and that it has established the existing allowance in accordance with GAAP. However, the determination of the allowance requires significant judgment, and estimates of expected lifetime losses in the loan portfolio can vary significantly from the amounts actually observed. While management uses available information to recognize expected losses, future additions to the allowance may be necessary based on changes in the loans comprising the portfolio, changes in the current and forecasted economic conditions, changes to the interest rate environment which may directly impact prepayment and curtailment rate assumptions, and changes in the financial condition of borrowers. The adoption of the CECL standard did not result in a significant change to any other credit risk management and monitoring processes, including identification of past due or delinquent borrowers, non-accrual charge-off
Allowance for Credit Losses - Off-Balance-Sheet/Reserve for Unfunded Commitments	Allowance for Credit Losses - Off-Balance-Sheet/Reserve The allowance for credit losses on off-balance-sheet
Other Real Estate	Other Real Estate Other real estate owned is foreclosed property held pending disposition and is initially recorded at fair value, less estimated costs to sell. At foreclosure, if the fair value of the real estate, less estimated costs to sell, is less than the Company’s recorded investment in the related loan, a write-down is recognized through a charge to the allowance for credit losses. Any subsequent reduction in value is recognized by a charge to income. Operating and holding expenses of such properties, net of related income, and gains and losses on their disposition are included in net gain (loss) on sale of foreclosed assets as incurred.
Bank Premises and Equipment	Bank Premises and Equipment Bank premises and equipment are stated at cost less accumulated depreciation and amortization. Depreciation and amortization are computed principally on a straight-line basis over the estimated useful lives of the related assets. Leasehold improvements are amortized over the life of the respective lease or the estimated useful lives of the improvements, whichever is shorter.
Business Combinations, Goodwill and Other Intangible Assets	Business Combinations, Goodwill and Other Intangible Assets The Company accounts for all business combinations under the purchase method of accounting. Tangible and intangible assets and liabilities of the acquired entity are recorded at fair value. Intangible assets with finite useful lives represent the future benefit associated with the acquisition of the core deposits and are amortized over seven years, utilizing a method that approximates the expected attrition of the deposits. Goodwill with an indefinite life is not amortized, but rather tested annually for impairment as of June 30 each year. There was no impairment recorded for the three or six-months
Securities Sold Under Agreements To Repurchase	Securities Sold Under Agreements To Repurchase Securities sold under agreements to repurchase, which are classified as borrowings, generally mature within one to four days from the transaction date. Securities sold under agreements to repurchase are reflected at the amount of the cash received in connection with the transaction. The Company may be required to provide additional collateral based on the estimated fair value of the underlying securities.
Segment Reporting	Segment Reporting The Company has determined that its banking regions meet the aggregation criteria of the current authoritative accounting guidance since each of its banking regions offer similar products and services, operate in a similar manner, have similar customers and report to the same regulatory authority, and therefore operate one line of business (community banking) located in a single geographic area (Texas).
Statements of Cash Flows	Statements of Cash Flows For purposes of reporting cash flows, cash and cash equivalents includes cash on hand, amounts due from banks, including interest-bearing demand deposits in banks with original maturity of 90 days or less, and federal funds sold.
Accumulated Other Comprehensive Earnings (Loss)	Accumulated Other Comprehensive Earnings (Loss) Unrealized net gains on the Company’s available-for-sale
Income Taxes	Income Taxes The Company’s provision for income taxes is based on income before income taxes adjusted for permanent differences between financial reporting and taxable income. Deferred tax assets and liabilities are determined using the liability (or balance sheet) method. Under this method, the net deferred tax asset or liability is determined based on the tax effects of the temporary differences between the book and tax bases of the various balance sheet assets and liabilities and gives current recognition to changes in tax rates and laws.
Stock Based Compensation	Stock Based Compensation The Company grants stock options for a fixed number of shares to employees with an exercise price equal to the fair value of the shares at the grant date. The grant date fair value is amortized over the shorter of the service period or vesting period which generally is six years. The Company also grants restricted stock for a fixed number of shares. The grant date fair value is amortized over the vesting period which generally is one to three years. See Note 8 for further information.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred.
Per Share Data	Per Share Data Net earnings per share (“EPS”) are computed by dividing net earnings by the weighted average number of common shares outstanding during the period. The Company calculates dilutive EPS assuming all outstanding stock options to purchase common shares and unvested restricted stock shares have been exercised and/or vested at the beginning of the year (or the time of issuance, if later.) The dilutive effect of the outstanding options and restricted stock is reflected by application of the treasury stock method, whereby the proceeds from the exercised options and unearned compensation for both restricted stock and stock options are assumed to be used to purchase common shares at the average market price during the respective period. There were no anti-dilutive shares for the three or six-months six-months Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the three-months ended June 30, 2021: Net earnings per share, basic $ 56,379 142,245,555 $ 0.40 Effect of stock options and stock grants — 919,056 (0.01 ) Net earnings per share, diluted $ 56,379 143,164,611 $ 0.39 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the six-months Net earnings per share, basic $ 113,297 142,196,190 $ 0.80 Effect of stock options and stock grants — 906,418 (0.01 ) Net earnings per share, diluted $ 113,297 143,102,608 $ 0.79 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the three-months ended June 30, 2020: Net earnings per share, basic $ 53,470 141,973,522 $ 0.38 Effect of stock options and stock grants — 480,561 — Net earnings per share, diluted $ 53,470 142,454,083 $ 0.38 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the six-months Net earnings per share, basic $ 90,701 142,045,779 $ 0.64 Effect of stock options and stock grants — 473,529 — Net earnings per share, diluted $ 90,701 142,519,308 $ 0.64

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Computation of Basic EPS to Dilutive EPS	The following table reconciles the computation of basic EPS to diluted EPS: Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the three-months ended June 30, 2021: Net earnings per share, basic $ 56,379 142,245,555 $ 0.40 Effect of stock options and stock grants — 919,056 (0.01 ) Net earnings per share, diluted $ 56,379 143,164,611 $ 0.39 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the six-months Net earnings per share, basic $ 113,297 142,196,190 $ 0.80 Effect of stock options and stock grants — 906,418 (0.01 ) Net earnings per share, diluted $ 113,297 143,102,608 $ 0.79 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the three-months ended June 30, 2020: Net earnings per share, basic $ 53,470 141,973,522 $ 0.38 Effect of stock options and stock grants — 480,561 — Net earnings per share, diluted $ 53,470 142,454,083 $ 0.38 Net Weighted Earnings Average Per Share (in thousands) Shares Amount For the six-months Net earnings per share, basic $ 90,701 142,045,779 $ 0.64 Effect of stock options and stock grants — 473,529 — Net earnings per share, diluted $ 90,701 142,519,308 $ 0.64

Securities (Tables)

Securities (Tables)	6 Months Ended
	Jun. 30, 2021
Cash and Cash Equivalents [Abstract]
Summary of Available-for-Sale Securities	The amortized cost, related gross unrealized gains and losses, allowance for credit losses and the fair value of available-for-sale June 30, 2021 Gross Gross Amortized Unrealized Unrealized Estimated Cost Basis Holding Gains Holding Losses Fair Value Securities available-for-sale: Obligations of states and political subdivisions $ 2,490,468 $ 125,612 $ (993 ) $ 2,615,087 Residential mortgage-backed securities 2,471,278 38,619 (5,711 ) 2,504,186 Commercial mortgage-backed securities 405,146 15,822 — 420,968 Corporate bonds and other 38,297 91 (581 ) 37,807 Total securities available-for-sale $ 5,405,189 $ 180,144 $ (7,285 ) $ 5,578,048 June 30, 2020 Gross Gross Amortized Unrealized Unrealized Estimated Cost Basis Holding Gains Holding Losses Fair Value Securities available-for-sale: U.S. Treasury securities $ 10,083 $ 40 $ (1 ) $ 10,122 Obligations of states and political subdivisions 1,836,572 113,757 (50 ) 1,950,279 Residential mortgage-backed securities 1,517,139 54,652 (118 ) 1,571,673 Commercial mortgage-backed securities 559,062 23,159 (1 ) 582,220 Corporate bonds and other 4,398 171 — 4,569 Total securities available-for-sale $ 3,927,254 $ 191,779 $ (170 ) $ 4,118,863 December 31, 2020 Gross Gross Amortized Unrealized Unrealized Estimated Cost Basis Holding Gains Holding Losses Fair Value Securities available-for-sale: Obligations of states and political subdivisions $ 2,283,616 $ 143,339 $ (79 ) $ 2,426,876 Residential mortgage-backed securities 1,421,922 50,473 (115 ) 1,472,280 Commercial mortgage-backed securities 467,243 22,077 (4 ) 489,316 Corporate bonds and other 4,398 159 — 4,557 Total securities available-for-sale $ 4,177,179 $ 216,048 $ (198 ) $ 4,393,029
Amortized Cost and Estimated Fair Value of Available-for-Sale Securities	The amortized cost and estimated fair value of available-for-sale Amortized Estimated Cost Basis Fair Value Due within one year $ 297,211 $ 301,535 Due after one year through five years 2,493,104 2,586,178 Due after five years through ten years 2,506,074 2,581,554 Due after ten years 108,800 108,781 Total $ 5,405,189 $ 5,578,048
Continuous Unrealized-Loss Position of Available-for-Sale Securities	The following tables disclose the Company’s investment securities that have been in a continuous unrealized-loss Less than 12 Months 12 Months or Longer Total June 30, 2021 Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized Obligations of states and political subdivisions $ 170,483 $ 992 $ — $ — $ 170,483 $ 992 Residential mortgage-backed securities 712,100 5,706 2,478 6 714,578 5,712 Commercial mortgage-backed securities 866 — — — 866 — Corporate bonds and other 33,318 581 — — 33,318 581 Total $ 916,767 $ 7,279 $ 2,478 $ 6 $ 919,245 $ 7,285 Less than 12 Months 12 Months or Longer Total June 30, 2020 Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized U.S. Treasury securities $ 5,055 $ 1 $ — $ — $ 5,055 $ 1 Obligations of states and political subdivisions 18,249 50 — — 18,249 50 Residential mortgage-backed securities 12,590 45 6,454 73 19,044 118 Commercial mortgage-backed securities 4,936 1 — — 4,936 1 Total $ 40,830 $ 97 $ 6,454 $ 73 $ 47,284 $ 170 Less than 12 Months 12 Months or Longer Total December 31, 2020 Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized Obligations of state and political subdivisions $ 25,214 $ 79 $ — $ — $ 25,214 $ 79 Residential mortgage-backed securities 36,017 96 3,156 19 39,173 115 Commercial mortgage-backed securities 16,218 4 — — 16,218 4 Total $ 77,449 $ 179 $ 3,156 $ 19 $ 80,605 $ 198

Loans Held for Investment and_2

Loans Held for Investment and Allowance for Loan Losses (Tables)	6 Months Ended
	Jun. 30, 2021
Receivables [Abstract]
Loans Held-for-Investment by Portfolio Segment	Loans held-for-investment June 30, December 31, 2021 2020 2020 Commercial: C&I* $ 983,103 $ N/A $ 1,131,382 Municipal 179,356 N/A 181,325 Total Commercial 1,162,459 1,509,454 1,312,707 Agricultural 95,212 97,448 94,864 Real Estate: Construction & Development 550,928 N/A 553,959 Farm 185,288 N/A 152,237 Non-Owner 673,608 N/A 617,686 Owner Occupied CRE 820,055 N/A 746,974 Residential 1,328,474 N/A 1,248,409 Total Real Estate 3,558,353 3,235,208 3,319,265 Consumer: Auto 383,764 N/A 353,595 Non-Auto 104,814 N/A 90,602 Total Consumer 488,578 410,957 444,197 Total Loans 5,304,602 5,253,067 5,171,033 Less: Allowance for credit losses (62,138 ) (68,947 ) (66,534 ) Loans, net $ 5,242,464 $ 5,184,120 $ 5,104,499 * All disclosures for the C&I loan segment include PPP loan balances, net of deferred loan fees, as disclosed on the face of the balance sheet on page 4.
Non-Accrual Loans, Loans Still Accruing and Past Due 90 Days or More and Restructured Loans	The Company’s non-accrual June 30, December 31, 2021 2020 2020 Non-accrual $ 29,786 $ 39,320 $ 42,619 Loans still accruing and past due 90 days or more — 92 113 Troubled debt restructured loans still accruing* 23 25 24 Total $ 29,809 $ 39,437 $ 42,756 * Troubled debt restructured loans of $7,305,000, $7,275,000 and $7,407,000, whose interest collection, after considering economic and business conditions and collection efforts, is doubtful are included in non-accrual
Schedule of Non-Accrual Loans	Non-accrual June 30, December 31, 2021 2020 2020 Commercial: C&I $ 3,587 $ N/A $ 5,015 Municipal — N/A — Total Commercial 3,587 4,618 5,015 Agricultural 1,055 1,056 1,076 Real Estate: Construction & Development 1,520 N/A 3,838 Farm 1,791 N/A 7,299 Non-Owner 6,584 N/A 5,243 Owner Occupied CRE 8,976 N/A 10,797 Residential 5,901 N/A 8,851 Total Real Estate 24,772 33,170 36,028 Consumer: Auto 329 N/A 407 Non-Auto 43 N/A 93 Total Consumer 372 476 500 Total $ 29,786 $ 39,320 $ 42,619
Changes in Allowance for Loan Losses	Summary information on the allowance for credit losses for the three and six-months Three-months ended June 30, 2021 C&I Municipal Agricultural Construction Farm Beginning balance $ 12,323 $ 2,191 $ 1,985 $ 13,246 $ 1,223 Provision for loan losses (2,327 ) (1,603 ) (667 ) 2,386 (617 ) Recoveries 308 — 15 — 1 Charge-offs (118 ) — (21 ) — — Ending balance $ 10,186 $ 588 $ 1,312 $ 15,632 $ 607 Three-months ended June 30, 2021 (continued) Non-Owner Owner Residential Auto Non-Auto Total Beginning balance $ 9,492 $ 9,878 $ 11,189 $ 1,068 $ 379 $ 62,974 Provision for loan losses 901 517 26 257 88 (1,039 ) Recoveries 39 4 64 103 61 595 Charge-offs — — (45 ) (162 ) (46 ) (392 ) Ending balance $ 10,432 $ 10,399 $ 11,234 $ 1,266 $ 482 $ 62,138 Six-months C&I Municipal Agricultural Construction Farm Beginning balance $ 13,609 $ 1,552 $ 1,255 $ 13,512 $ 1,876 Provision for loan losses (3,566 ) (964 ) 54 2,118 (1,279 ) Recoveries 531 — 24 2 10 Charge-offs (388 ) — (21 ) — — Ending balance $ 10,186 $ 588 $ 1,312 $ 15,632 $ 607 Six-months Non-Owner Owner Residential Auto Non- Total Beginning balance $ 8,391 $ 12,347 $ 12,601 $ 1,020 $ 371 $ 66,534 Provision for loan losses 1,953 (1,950 ) (1,358 ) 398 126 (4,468 ) Recoveries 94 10 83 176 108 1,038 Charge-offs (6 ) (8 ) (92 ) (328 ) (123 ) (966 ) Ending balance $ 10,432 $ 10,399 $ 11,234 $ 1,266 $ 482 $ 62,138 Three-months ended June 30, 2020 Commercial Agricultural Real Estate Consumer Total Beginning balance $ 11,773 $ 2,154 $ 41,256 $ 5,257 $ 60,440 Provision for loan losses 6,820 361 1,469 50 8,700 Recoveries 540 29 59 73 701 Charge-offs (561 ) — (161 ) (172 ) (894 ) Ending balance $ 18,572 $ 2,544 $ 42,623 $ 5,208 $ 68,947 Six-months Commercial Agricultural Real Estate Consumer Total Beginning balance $ 12,122 $ 1,206 $ 33,974 $ 5,197 $ 52,499 Provision for loan losses 7,615 1,310 9,390 235 18,550 Recoveries 690 30 135 164 1,019 Charge-offs (1,855 ) (2 ) (876 ) (388 ) (3,121 ) Ending balance $ 18,572 $ 2,544 $ 42,623 $ 5,208 $ 68,947
Schedule of loans that are individually evaluated for credit losses	The Company’s loans that are individually evaluated for credit losses (both collateral and non-collateral June 30, 2021 Collateral Collateral Non-Collateral Total Loans Related Related Non-Collateral Total Commercial: C&I $ 1,091 $ 2,496 $ 20,838 $ 24,425 $ 723 $ 3,865 $ 4,588 Municipal — — 885 885 — 275 275 Total Commercial 1,091 2,496 21,723 25,310 723 4,140 4,863 Agricultural 328 727 5,195 6,250 171 1,084 1,255 Real Estate: Construction & Development 1,282 238 9,201 10,721 24 1,075 1,099 Farm 1,697 94 2,745 4,536 — 9 9 Non-Owner 6,444 140 33,707 40,291 15 4,185 4,200 Owner Occupied CRE 5,605 3,371 42,832 51,808 544 2,600 3,144 Residential 3,762 2,139 28,110 34,011 191 2,418 2,609 Total Real Estate 18,790 5,982 116,595 141,367 774 10,287 11,061 Consumer: Auto — 329 1,342 1,671 1 4 5 Non-Auto — 43 353 396 — 2 2 Total Consumer — 372 1,695 2,067 1 6 7 Total $ 20,209 $ 9,577 $ 145,208 $ 174,994 $ 1,669 $ 15,517 $ 17,186 December 31, 2020 Collateral Collateral Non-Collateral Total Loans Related Related Non-Collateral Total Commercial: C&I $ 1,544 $ 3,471 $ 25,629 $ 30,644 $ 799 $ 4,592 $ 5,391 Municipal — — 9,439 9,439 — 1,435 1,435 Total Commercial 1,544 3,471 35,068 40,083 799 6,027 6,826 Agricultural 470 606 5,572 6,648 96 886 982 Real Estate: Construction & Development 1,176 2,661 11,368 15,205 35 617 652 Farm 2,614 4,685 3,349 10,648 654 658 1,312 Non-Owner 4,009 1,234 17,383 22,626 500 1,421 1,921 Owner Occupied CRE 7,279 3,518 51,933 62,730 657 5,172 5,829 Residential 4,347 4,504 28,196 37,047 676 2,431 3,107 Total Real Estate 19,425 16,602 112,229 148,256 2,522 10,299 12,821 Consumer: Auto — 407 1,523 1,930 1 5 6 Non-Auto — 94 440 534 1 1 2 Total Consumer — 501 1,963 2,464 2 6 8 Total $ 21,439 $ 21,180 $ 154,832 $ 197,451 $ 3,419 $ 17,218 $ 20,637 The following table presents the recorded investment with respect to impaired loans, the associated allowance by the applicable portfolio segment and the unpaid contractual principal balance of the impaired loans at June 30, 2020, in accordance with the legacy “incurred loss” methodology disclosure requirements (in thousands): June 30, 2020 Unpaid Recorded Recorded Total Related Year-to- Three- Commercial $ 6,013 $ 739 $ 3,879 $ 4,618 $ 1,250 $ 24,270 $ 23,572 Agricultural 1,287 529 527 1,056 83 219 179 Real Estate 45,703 20,370 12,800 33,170 1,711 17,586 17,107 Consumer 585 — 476 476 2 606 552 Total $ 53,588 $ 21,638 $ 17,682 $ 39,320 $ 3,046 $ 42,681 $ 41,410
Schedule of Allowance for Loan Losses by Portfolio Segment	The Company’s allowance for loans that are individually evaluated for credit losses and collectively evaluated for credit losses as of June 30, 2021 and December 31, 2020, are summarized in the following table by loan segment (in thousands). Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories. June 30, 2021 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 4,588 $ 275 $ 1,255 $ 1,099 $ 9 Loans collectively evaluated for credit losses 5,598 313 57 14,533 598 Total $ 10,186 $ 588 $ 1,312 $ 15,632 $ 607 June 30, 2021 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 4,200 $ 3,144 $ 2,609 $ 5 $ 2 $ 17,186 Loans collectively evaluated for credit losses 6,232 7,255 8,625 1,261 480 44,952 Total $ 10,432 $ 10,399 $ 11,234 $ 1,266 $ 482 $ 62,138 December 31, 2020 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 5,391 $ 1,435 $ 982 $ 652 $ 1,312 Loans collectively evaluated for credit losses 8,218 117 273 12,860 564 Total $ 13,609 $ 1,552 $ 1,255 $ 13,512 $ 1,876 December 31, 2020 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 1,921 $ 5,829 $ 3,107 $ 6 $ 2 $ 20,637 Loans collectively evaluated for credit losses 6,470 6,518 9,494 1,014 369 45,897 Total $ 8,391 $ 12,347 $ 12,601 $ 1,020 $ 371 $ 66,534 The Company’s allowance for loans that are individually evaluated for credit losses and collectively evaluated for credit losses as of June 30, 2020, are summarized in the following table by loan segment in accordance with the legacy “incurred loss” methodology disclosure requirements (in thousands): June 30, 2020 Commercial Agricultural Real Estate Consumer Total Loans individually evaluated for impairment $ 1,250 $ 83 $ 1,711 $ 2 $ 3,046 Loan collectively evaluated for impairment 17,322 2,461 40,912 5,206 65,901 Total $ 18,572 $ 2,544 $ 42,623 $ 5,208 $ 68,947
Schedule of Investment in Loans Related to Balance in Allowance for Loan Losses on Basis of Company's Impairment Methodology	The Company’s recorded investment in loans as of June 30, 2021 and December 31, 2020, related to the balance in the allowance for credit losses on the basis of the Company’s adopted ASC 326 evaluation methodology follows below (in thousands): June 30, 2021 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 24,425 $ 885 $ 6,250 $ 10,721 $ 4,536 Loans collectively evaluated for credit losses 958,678 178,471 88,962 540,207 180,752 Total $ 983,103 $ 179,356 $ 95,212 $ 550,928 $ 185,288 June 30, 2021 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 40,291 $ 51,808 $ 34,011 $ 1,671 $ 396 $ 174,994 Loans collectively evaluated for credit losses 633,317 768,247 1,294,463 382,093 104,418 5,129,608 Total $ 673,608 $ 820,055 $ 1,328,474 $ 383,764 $ 104,814 $ 5,304,602 December 31, 2020 C&I Municipal Agricultural Construction Farm Loans individually evaluated for credit losses $ 30,644 $ 9,439 $ 6,648 $ 15,205 $ 10,648 Loans collectively evaluated for credit losses 1,100,738 171,886 88,216 538,754 141,589 Total $ 1,131,382 $ 181,325 $ 94,864 $ 553,959 $ 152,237 December 31, 2020 (continued) Non-Owner Owner Residential Auto Non-Auto Total Loans individually evaluated for credit losses $ 22,626 $ 62,730 $ 37,047 $ 1,930 $ 534 $ 197,451 Loans collectively evaluated for credit losses 595,060 684,244 1,211,362 351,665 90,068 4,973,582 Total $ 617,686 $ 746,974 $ 1,248,409 $ 353,595 $ 90,602 $ 5,171,033 The Company’s recorded investment in loans as of June 30, 2020, related to the balance in the allowance for loan losses on the basis of the Company’s legacy “incurred loss” impairment methodology follows below (in thousands): June 30, 2020 Commercial Agricultural Real Estate Consumer Total Loans individually evaluated for impairment $ 4,618 $ 1,056 $ 33,170 $ 476 $ 39,320 Loan collectively evaluated for impairment 1,504,836 96,392 3,202,038 410,481 5,213,747 Total $ 1,509,454 $ 97,448 $ 3,235,208 $ 410,957 $ 5,253,067
Schedule of Company's Internal Ratings of its Loans Held-for-Investment, Including The Year of Origination, by Portfolio Segments	The following summarizes the Company’s internal ratings of its loans held-for-investment, June 30, 2021 2020 2019 2018 2017 Prior Revolving Total C&I Risk rating: Pass $ 485 $ 316 $ 71 $ 46 $ 22 $ 19 $ — $ 959 Special mention 4 2 1 1 1 — — 9 Substandard 4 6 2 3 — — — 15 Doubtful — — — — — — — — Total $ 493 $ 324 $ 74 $ 50 $ 23 $ 19 $ — $ 983 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Municipal Risk rating: Pass $ 23 $ 23 $ 8 $ 22 $ 18 $ 84 $ — $ 178 Special mention — — — — — — — — Substandard — — — — — 1 — 1 Doubtful — — — — — — — — Total $ 23 $ 23 $ 8 $ 22 $ 18 $ 85 $ — $ 179 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Agricultural Risk rating: Pass $ 30 $ 34 $ 15 $ 7 $ 3 $ 1 $ — $ 90 Special mention — — — — — — — — Substandard — 5 — — 1 — — 6 Doubtful — — — — — — — — Total $ 30 $ 39 $ 15 $ 7 $ 4 $ 1 $ — $ 96 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Construction & Development Risk rating: Pass $ 220 $ 237 $ 39 $ 18 $ 9 $ 17 $ — $ 540 Special mention 1 2 — — — — — 3 Substandard 2 2 4 — — — — 8 Doubtful — — — — — — — — Total $ 223 $ 241 $ 43 $ 18 $ 9 $ 17 $ — $ 551 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Farm Risk rating: Pass $ 59 $ 53 $ 17 $ 12 $ 9 $ 31 $ — $ 181 Special mention — — — — — — — — Substandard — 2 — 1 — 1 — 4 Doubtful — — — — — — — — Total $ 59 $ 55 $ 17 $ 13 $ 9 $ 32 $ — $ 185 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Non-Owner Risk rating: Pass $ 101 $ 171 $ 104 $ 80 $ 40 $ 138 $ — $ 634 Special mention — 1 13 1 7 3 — 25 Substandard 2 — 3 — 3 7 — 15 Doubtful — — — — — — — — Total $ 103 $ 172 $ 120 $ 81 $ 50 $ 148 $ — $ 674 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Owner Occupied CRE Risk rating: Pass $ 137 $ 178 $ 129 $ 103 $ 64 $ 157 $ — $ 768 Special mention 1 2 1 1 4 1 — 10 Substandard 8 3 5 14 2 10 — 42 Doubtful — — — — — — — — Total $ 146 $ 183 $ 135 $ 118 $ 70 $ 168 $ — $ 820 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Residential Risk rating: Pass $ 266 $ 316 $ 145 $ 105 $ 84 $ 282 $ 96 $ 1,294 Special mention — 3 1 1 1 3 — 9 Substandard 2 5 3 2 2 10 1 25 Doubtful — — — — — — — — Total $ 268 $ 324 $ 149 $ 108 $ 87 $ 295 $ 97 $ 1,328 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Auto Risk rating: Pass $ 118 $ 140 $ 76 $ 26 $ 13 $ 9 $ — $ 382 Special mention — — — — — — — — Substandard — 1 1 — — — — 2 Doubtful — — — — — — — — Total $ 118 $ 141 $ 77 $ 26 $ 13 $ 9 $ — $ 384 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Non-Auto Risk rating: Pass $ 40 $ 33 $ 14 $ 5 $ 2 $ 5 $ 6 $ 105 Special mention — — — — — — — — Substandard — — — — — — — — Doubtful — — — — — — — — Total $ 40 $ 33 $ 14 $ 5 $ 2 $ 5 $ 6 $ 105 June 30, 2021 2020 2019 2018 2017 Prior Revolving Total Total Loans Risk rating: Pass $ 1,479 $ 1,501 $ 618 $ 424 $ 264 $ 743 $ 102 $ 5,131 Special mention 6 10 16 4 13 7 — 56 Substandard 18 24 18 20 8 29 1 118 Doubtful — — — — — — — — Total $ 1,503 $ 1,535 $ 652 $ 448 $ 285 $ 779 $ 103 $ 5,305 The following summarizes the Company’s internal ratings of its loans held-for-investment, December 31, 2020 2019 2018 2017 2016 Prior Revolving Total C&I Risk rating: Pass $ 874 $ 101 $ 70 $ 28 $ 10 $ 16 $ — $ 1,099 Special mention 9 2 — 1 — — — 12 Substandard 12 4 4 — — — — 20 Doubtful — — — — — — — — Total $ 895 $ 107 $ 74 $ 29 $ 10 $ 16 $ — $ 1,131 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Municipal Risk rating: Pass $ 26 $ 19 $ 29 $ 14 $ 13 $ 71 $ — $ 172 Special mention — — — — — — — — Substandard 2 — — 5 1 1 — 9 Doubtful — — — — — — — — Total $ 28 $ 19 $ 29 $ 19 $ 14 $ 72 $ — $ 181 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Agricultural Risk rating: Pass $ 57 $ 19 $ 9 $ 3 $ 1 $ — $ — $ 89 Special mention — — — — — — — — Substandard 6 — — — — — — 6 Doubtful — — — — — — — — Total $ 63 $ 19 $ 9 $ 3 $ 1 $ — $ — $ 95 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Construction & Development Risk rating: Pass $ 371 $ 97 $ 36 $ 19 $ 7 $ 9 $ — $ 539 Special mention 2 4 — — — — — 6 Substandard 4 1 — 3 — 1 — 9 Doubtful — — — — — — — — Total $ 377 $ 102 $ 36 $ 22 $ 7 $ 10 $ — $ 554 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Farm Risk rating: Pass $ 57 $ 22 $ 18 $ 11 $ 11 $ 23 $ — $ 142 Special mention — — — — — — — — Substandard 7 1 — 1 — 1 — 10 Doubtful — — — — — — — — Total $ 64 $ 23 $ 18 $ 12 $ 11 $ 24 $ — $ 152 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Non-Owner Risk rating: Pass $ 197 $ 117 $ 93 $ 44 $ 55 $ 88 $ — $ 594 Special mention 1 — 1 8 1 — — 11 Substandard — 2 — — — 11 — 13 Doubtful — — — — — — — — Total $ 198 $ 119 $ 94 $ 52 $ 56 $ 99 $ — $ 618 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Owner Occupied CRE Risk rating: Pass $ 176 $ 132 $ 105 $ 75 $ 65 $ 132 $ — $ 685 Special mention 5 5 2 4 1 1 — 18 Substandard 5 4 20 4 1 10 — 44 Doubtful — — — — — — — — Total $ 186 $ 141 $ 127 $ 83 $ 67 $ 143 $ — $ 747 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Residential Risk rating: Pass $ 373 $ 172 $ 134 $ 101 $ 101 $ 237 $ 93 $ 1,211 Special mention 3 1 1 1 1 3 — 10 Substandard 5 3 3 3 1 10 2 27 Doubtful — — — — — — — — Total $ 381 $ 176 $ 138 $ 105 $ 103 $ 250 $ 95 $ 1,248 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Auto Risk rating: Pass $ 177 $ 104 $ 39 $ 21 $ 9 $ 2 $ — $ 352 Special mention — — — — — — — — Substandard 1 1 — — — — — 2 Doubtful — — — — — — — — Total $ 178 $ 105 $ 39 $ 21 $ 9 $ 2 $ — $ 354 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Non-Auto Risk rating: Pass $ 48 $ 21 $ 7 $ 4 $ 1 $ 2 $ 7 $ 90 Special mention — — — — — — — — Substandard — — — — — 1 — 1 Doubtful — — — — — — — — Total $ 48 $ 21 $ 7 $ 4 $ 1 $ 3 $ 7 $ 91 December 31, 2020 2019 2018 2017 2016 Prior Revolving Total Total Loans Risk rating: Pass $ 2,356 $ 804 $ 540 $ 320 $ 273 $ 580 $ 100 $ 4,973 Special mention 20 12 4 14 3 4 — 57 Substandard 42 16 27 16 3 35 2 141 Doubtful — — — — — — — — Total $ 2,418 $ 832 $ 571 $ 350 $ 279 $ 619 $ 102 $ 5,171
Schedule of Internal Ratings of Loans	The following tables summarize the Company’s internal ratings of its loans held-for-investment, June 30, 2020 Pass Special Substandard Doubtful Total Commercial $ 1,465 $ 9 $ 35 $ — $ 1,509 Agricultural 91 5 2 — 98 Real Estate 3,087 50 98 — 3,235 Consumer 409 — 2 — 411 Total $ 5,052 $ 64 $ 137 $ — $ 5,253
Schedule of Past Due Loans	The Company’s past due loans are as follows (in thousands): June 30, 2021 15-59 60-89 Greater Total Past Current Total Loans 90 Days Commercial: C&I $ 3,432 $ 707 $ 230 $ 4,369 $ 978,734 $ 983,103 $ — Municipal 1,656 — — 1,656 177,700 179,356 — Total Commercial 5,088 707 230 6,025 1,156,434 1,162,459 — Agricultural 193 10 35 238 94,974 95,212 — Real Estate: Construction & Development 1,973 — 162 2,135 548,793 550,928 — Farm 1,138 — — 1,138 184,150 185,288 — Non-Owner 896 161 — 1,057 672,551 673,608 — Owner Occupied CRE 97 821 — 918 819,137 820,055 — Residential 5,946 373 100 6,419 1,322,055 1,328,474 — Total Real Estate 10,050 1,355 262 11,667 3,546,686 3,558,353 — Consumer: Auto 330 55 25 410 383,354 383,764 — Non-Auto 44 11 — 55 104,759 104,814 — Total Consumer 374 66 25 465 488,113 488,578 — Total $ 15,705 $ 2,138 $ 552 $ 18,395 $ 5,286,207 $ 5,304,602 $ — December 31, 2020 15-59 60-89 Greater Total Past Current Total Loans 90 Days Commercial: C&I $ 3,647 $ 406 $ 576 $ 4,629 $ 1,126,753 $ 1,131,382 $ 21 Municipal — — — — 181,325 181,325 — Total Commercial 3,647 406 576 4,629 1,308,078 1,312,707 21 Agricultural 193 95 — 288 94,576 94,864 — Real Estate: Construction & Development 4,775 44 — 4,819 549,140 553,959 — Farm 708 — — 708 151,529 152,237 — Non-Owner 613 — — 613 617,073 617,686 — Owner Occupied CRE 1,393 322 133 1,848 745,126 746,974 — Residential 8,072 18 275 8,365 1,240,044 1,248,409 33 Total Real Estate 15,561 384 408 16,353 3,302,912 3,319,265 33 Consumer: Auto 551 158 75 784 352,811 353,595 59 Non-Auto 214 24 — 238 90,364 90,602 — Total Consumer 765 182 75 1,022 443,175 444,197 59 Total $ 20,166 $ 1,067 $ 1,059 $ 22,292 $ 5,148,741 $ 5,171,033 $ 113 June 30, 2020 15-59 60-89 Greater Total Current Total Loans 90 Days Commercial $ 4,563 $ 474 $ 129 $ 5,166 $ 1,504,288 $ 1,509,454 $ — Agricultural 1,080 15 — 1,095 96,353 97,448 — Real Estate 13,678 110 726 14,514 3,220,694 3,235,208 — Consumer 410 83 105 598 410,359 410,957 92 Total $ 19,731 $ 682 $ 960 $ 21,373 $ 5,231,694 $ 5,253,067 $ 92 * The Company monitors commercial, agricultural and real estate loans after such loans are 15 days past due. Consumer loans are monitored after such loans are 30 days past due.
Schedule of Loans Modified and Considered Troubled Debt Restructurings	The Company’s loans that were modified and considered troubled debt restructurings are as follows (in thousands): Three-Months Ended June 30, 2021 Six-Months Pre- Modification Post- Modification Pre- Modification Post- Modification Recorded Recorded Recorded Recorded Number Investment Investment Number Investment Investment Commercial: C&I 2 $ 212 $ 212 4 $ 361 $ 361 Municipal — — — — — — Total Commercial 2 212 212 4 361 361 Agricultural 1 68 68 1 68 68 Real Estate: Construction & Development 1 200 200 1 200 200 Farm — — — — — — Non-Owner — — — — — — Owner Occupied CRE 2 548 548 3 1,047 1,047 Residential 1 245 245 3 443 443 Total Real Estate 4 993 993 7 1,690 1,690 Consumer: Auto 1 31 31 1 31 31 Non-Auto — — — — — — Total Consumer 1 31 31 1 31 31 Total 8 $ 1,304 $ 1,304 13 $ 2,150 $ 2,150 Three-Months Ended June 30, 2020 Six-Months Pre- Modification Post- Pre- Modification Post- Recorded Recorded Recorded Recorded Number Investment Investment Number Investment Investment Commercial 4 $ 196 $ 196 9 $ 484 $ 484 Agricultural — — — 1 134 134 Real Estate 1 123 123 1 123 123 Consumer — — — 1 14 14 Total 5 $ 319 $ 319 12 $ 755 $ 755
Schedule of How Loans Were Modified as Troubled Debt Restructured Loans	The balances below provide information as to how the loans were modified as troubled debt restructured loans (in thousands): Three-Months Ended June 30, 2021 Six-Months Adjusted Combined Adjusted Combined Interest Maturity Rate and Interest Maturity Rate and Rate Extended Maturity Rate Extended Maturity Commercial: C&I $ — $ 212 $ — $ — $ 212 $ 149 Municipal — — — — — — Total Commercial — 212 — — 212 149 Agricultural — 68 — — 68 — Real Estate: Construction & Development — 200 — — 200 — Farm — — — — — — Non-Owner — — — — — — Owner Occupied CRE — — 548 — — 1,047 Residential — 245 — — 245 198 Total Real Estate — 445 548 — 445 1,245 Consumer: Auto — — 31 — — 31 Non-Auto — — — — — — Total Consumer — — 31 — — 31 Total $ — $ 725 $ 579 $ — $ 725 $ 1,425 Three-Months Ended June 30, 2020 Six-Months Adjusted Combined Adjusted Combined Interest Maturity Rate and Interest Maturity Rate and Rate Extended Maturity Rate Extended Maturity Commercial $ — $ — $ 196 $ — $ 260 $ 224 Agricultural — — — — 134 — Real Estate — — 123 — — 123 Consumer — — — — 14 — Total $ — $ — $ 319 $ — $ 408 $ 347

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Outstanding Notional Balances and Fair Values of Outstanding Derivative Positions	The following table provides the outstanding notional balances and fair values of outstanding derivative positions (in thousands): June 30, 2021: Outstanding Asset Liability IRLCs $ 143,879 $ 2,670 $ — Forward mortgage-backed securities trades 165,000 — 376 June 30, 2020: Outstanding Asset Liability IRLCs $ 190,431 $ 5,037 $ — Forward mortgage-backed securities trades 201,500 — 1,099 December 31, 2020: Outstanding Asset Liability IRLCs $ 202,906 $ 4,618 $ — Forward mortgage-backed securities trades 198,000 — 1,560

Borrowings (Tables)

Borrowings (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Schedule of Borrowings	Borrowings consisted of the following (dollars in thousands): June 30, December 31, 2021 2020 2020 Securities sold under agreements with customers to repurchase $ 531,469 $ 444,249 $ 412,743 Federal funds purchased 18,500 4,975 17,350 Advances from Federal Home Loan Bank of Dallas — — — Total $ 549,969 $ 449,224 $ 430,093

Stock Option Plan and Restric_2

Stock Option Plan and Restricted Stock Plan (Tables)	6 Months Ended
	Jun. 30, 2021
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Analysis of Stock Option Activity	An analysis of stock option activity for the six-months Shares Weighted- Outstanding, December 31, 2020 1,833,057 $ 20.85 Granted — — Exercised (165,371 ) 15.89 Cancelled (17,600 ) 25.61 Outstanding, June 30, 2021 1,650,086 21.29 Exercisable, June 30, 2021 938,436 $ 19.04
Summary of Vested and Unvested Restricted Stock Outstanding	The following table summarizes information about vested and unvested restricted stock. For the six-months 2021 2020 Restricted Weighted Restricted Weighted Balance at beginning of period 95,888 $ 29.89 105,309 $ 29.93 Grants 12,110 49.58 32,149 28.55 Vesting (31,081 ) 28.42 (30,276 ) 30.27 Forfeited/expired (1,027 ) 34.55 (239 ) 29.70 Balance at end of period 75,890 $ 33.57 106,943 $ 29.42

Fair Value Disclosures (Tables)

Fair Value Disclosures (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis	The following table summarizes the Company’s available-for-sale held-for-sale, June 30, 2021 Level 1 Level 2 Level 3 Total Fair Available-for-sale Obligations of states and political subdivisions $ — $ 2,615,087 $ — $ 2,615,087 Corporate bonds — 33,318 — 33,318 Residential mortgage-backed securities — 2,504,186 — 2,504,186 Commercial mortgage-backed securities — 420,968 — 420,968 Other securities 4,489 — — 4,489 Total $ 4,489 $ 5,573,559 $ — $ 5,578,048 Loans held-for-sale $ — $ 56,257 $ — $ 56,257 IRLCs $ — $ 2,670 $ — $ 2,670 Forward mortgage-backed securities trades liability $ — $ (376 ) $ — $ (376 ) June 30, 2020 Level 1 Level 2 Level 3 Total Fair Available-for-sale U.S. Treasury securities $ 10,122 $ — $ — $ 10,122 Obligations of states and political subdivisions — 1,950,279 — 1,950,279 Residential mortgage-backed securities — 1,571,673 — 1,571,673 Commercial mortgage-backed securities — 582,220 — 582,220 Other securities 4,569 — — 4,569 Total $ 14,691 $ 4,104,172 $ — $ 4,118,863 Loans held-for-sale $ — $ 63,293 $ — $ 63,293 IRLCs $ — $ 5,037 $ — $ 5,037 Forward mortgage-backed securities trades liability $ — $ (1,099 ) $ — $ (1,099 ) December 31, 2020 Level 1 Level 2 Level 3 Total Fair Available-for-sale Obligations of state and political subdivisions $ — $ 2,426,876 $ — $ 2,426,876 Residential mortgage-backed securities — 1,472,280 — 1,472,280 Commercial mortgage-backed securities — 489,316 — 489,316 Other securities 4,557 — — 4,557 Total $ 4,557 $ 4,388,472 $ — $ 4,393,029 Loans held-for-sale $ — $ 79,585 $ — $ 79,585 IRLCs $ — $ 4,618 $ — $ 4,618 Forward mortgage-backed securities trades liability $ — $ (1,560 ) $ — $ (1,560 )
Summary of Loans Held-for-Sale at Fair Value	The following table summarizes the Company’s loans held-for-sale June 30, December 31, 2021 2020 2020 Unpaid principal balance on loans held-for-sale $ 54,542 $ 60,432 $ 76,602 Net unrealized gains on loans held-for-sale 1,715 2,861 2,983 Loans held-for-sale $ 56,257 $ 63,293 $ 79,585
Summary of Gain Loss on Sale of Mortgage Loans	The following table summarizes the Company’s gains on sale and fees of mortgage loans for the three and six-months ended June 30, 2021 and 2020 (in thousand): Three-Months ended Six-Months 2021 2020 2021 2020 Realized gain on sale and fees on mortgage loans* $ 9,465 $ 7,637 $ 20,195 $ 10,103 Change in fair value on loans held-for-sale 2,008 3,937 (3,193 ) 6,292 Change in forward mortgage-backed securities trades (3,182 ) 2,102 1,183 (946 ) Total gain on sale of mortgage loans $ 8,291 $ 13,676 $ 18,185 $ 15,449 * This includes gains on loans held-for-sale
Schedule of Estimated Fair Values and Carrying Values of All Financial Instruments	The estimated fair values and carrying values of all financial instruments under current authoritative guidance were as follows (in thousands). June 30, December 31, 2021 2020 2020 Carrying Estimated Carrying Estimated Carrying Estimated Fair Value Cash and due from banks $ 190,061 $ 190,061 $ 188,373 $ 188,373 $ 211,113 $ 211,113 Level 1 Interest-bearing demand deposits in banks 654,531 654,531 196,426 196,426 517,971 517,971 Level 1 Available-for-sale 5,578,048 5,578,048 4,118,863 4,118,863 4,393,029 4,393,029 Levels 1 Loans held-for-investment, 5,242,464 5,273,264 5,184,120 5,174,126 5,104,499 5,109,885 Level 3 Loans held-for-sale 61,802 61,969 66,370 66,630 83,969 84,233 Level 2 Accrued interest receivable 54,128 54,128 45,801 45,801 53,433 53,433 Level 2 Deposits with stated maturities 470,481 471,857 466,122 468,819 475,542 477,218 Level 2 Deposits with no stated maturities 9,311,213 9,311,213 7,691,520 7,691,520 8,200,275 8,200,275 Level 1 Borrowings 549,969 549,969 449,224 449,224 430,093 430,093 Level 2 Accrued interest payable 316 316 541 541 377 377 Level 2 IRLCs 2,670 2,670 5,037 5,037 4,618 4,618 Level 2 Forward mortgage-backed securities trades liability (376 ) (376 ) (1,099 ) (1,099 ) (1,560 ) (1,560 ) Level 2

Acquisition (Tables)

Acquisition (Tables)	6 Months Ended
	Jun. 30, 2021
Schedule of Preliminary Estimated Fair Value Amounts Assigned to Major Asset and Liability Categories at Acquisition Date	The following table presents the final amounts recorded on the consolidated balance sheet on the acquisition date (dollars in thousands): Fair value of consideration paid: Common stock issued (6,275,574 shares) $ 220,273 Fair value of identifiable assets acquired: Cash and cash equivalents $ 61,028 Securities available-for-sale 93,967 Loans 447,702 Identifiable intangible assets 4,798 Other assets 25,377 Total identifiable assets acquired $ 632,872 Fair value of liabilities assumed: Deposits $ 549,125 Other liabilities 5,397 Total liabilities assumed $ 554,522 Fair value of net identifiable assets acquired 78,350 Goodwill resulting from acquisition $ 141,923

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)	May 05, 2021USD ($)	Jun. 30, 2021USD ($)shares	Jun. 30, 2020USD ($)shares	Jun. 30, 2021USD ($)Locationshares	Jun. 30, 2020USD ($)shares	Dec. 31, 2020USD ($)	Jul. 27, 2021shares	Mar. 27, 2020USD ($)	Mar. 12, 2020shares	Jan. 01, 2020
Equity, Class of Treasury Stock [Line Items]
Number of locations | Location				78
Minimum number of shares that company is required to repurchase | shares				0
Treasury Stock, Value, Acquired	$ 8,008,000
Minimum number of days to consider the loans as non-accrual				90 days
Impairment recorded		$ 0	$ 0	$ 0	$ 0
Other identifiable intangible assets, amortized period (years)				7 years
Securities sold under agreements to repurchase maturity range (in days)				one to four days
Interest-bearing time deposits, maturity period (in days)				90 days or less
Unrealized net gains in available-for-sale securities, included in accumulated other comprehensive income		136,486,000	151,236,000	$ 136,486,000	151,236,000	$ 170,395,000
Retained earnings net of tax after transitional charges		$ 910,171,000	$ 762,830,000	$ 910,171,000	$ 762,830,000	836,729,000		$ 466,000
First financial antidilutive securities excluded from eps computation | shares		0	448,000	0	35,000
Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Shares repurchased under stock repurchase authorization, shares | shares				324,802	(324,802)
Allowance for Credit Losses [Member]
Equity, Class of Treasury Stock [Line Items]
Increase (decrease) in valuation and qualifying accounts and reserves from adjustment						(619,000)
Reserve for Unfunded Commitments [Member]
Equity, Class of Treasury Stock [Line Items]
Increase (decrease) in valuation and qualifying accounts and reserves from adjustment						1,208,000
Cumulative Effect, Period of Adoption, Adjustment [Member]
Equity, Class of Treasury Stock [Line Items]
Retained earnings net of tax after transitional charges								$ 589,000
Commitments to Extend Credit [Member]
Equity, Class of Treasury Stock [Line Items]
Reserve for losses on unfunded commitments		$ 6,751,000	$ 809,000	$ 6,751,000	$ 809,000	5,486,000
Held-to-maturity Securities [Member]
Equity, Class of Treasury Stock [Line Items]
Securities held to maturity		$ 0	$ 0	$ 0	$ 0	$ 0
Commercial Bancshares Inc and Commercial State Bank [Member]
Equity, Class of Treasury Stock [Line Items]
Percentage of common stock acquired										100.00%
Maximum [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, number of shares authorized to be repurchased | shares							5,000,000		4,000,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Computation of Basic EPS to Dilutive EPS (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net earnings per share, basic, Net Earnings	$ 56,379	$ 53,470	$ 113,297	$ 90,701
Effect of stock options and stock grants, Net Earnings
Net earnings per share, diluted, Net Earnings	$ 56,379	$ 53,470	$ 113,297	$ 90,701
Net earnings per share, basic, Weighted Average Shares	142,245,555	141,973,522	142,196,190	142,045,779
Effect of stock options and stock grants, Weighted Average Shares	919,056	480,561	906,418	473,529
Net earnings per share, diluted, Weighted Average Shares	143,164,611	142,454,083	143,102,608	142,519,308
Net earnings per share, basic, Per Share Amount	$ 0.40	$ 0.38	$ 0.80	$ 0.64
Effect of stock options and stock grants, Per Share Amount	(0.01)		(0.01)
Net earnings per share, diluted, Per Share Amount	$ 0.39	$ 0.38	$ 0.79	$ 0.64

Securities - Additional Informa

Securities - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)Investment	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)Investment	Jun. 30, 2020USD ($)
Interest Bearing Time Deposits In Banks And Securities [Line Items]
Interest-bearing time deposits, maturity period, years			12 months
Number of investment positions | Investment	77		77
Securities pledged as collateral	$ 3,222,472,000		$ 3,222,472,000
Sales of investment securities available-for-sale		$ 157,521,000	10,631,000	$ 252,958,000
Gross realized gains from security sales	$ 5,000	$ 1,516,000	813,000	3,578,000
Gross realized losses from security sales or calls			$ 0	$ 4,000
Obligations of State and Political Subdivisions [Member] | Texas [Member]
Interest Bearing Time Deposits In Banks And Securities [Line Items]
Percentage of securities guaranteed by Texas Permanent School Fund	53.09%		53.09%
Obligations of State and Political Subdivisions [Member] | Texas [Member] | Available-for-Sale Securities [Member] | Geographic Concentration Risk [Member]
Interest Bearing Time Deposits In Banks And Securities [Line Items]
Concentration risk, percentage			76.39%

Securities - Summary of Availab

Securities - Summary of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale, Amortized Cost Basis, Total	$ 5,405,189	$ 4,177,179	$ 3,927,254
Securities available-for-sale, Gross Unrealized Holding Gains	180,144	216,048	191,779
Securities available-for-sale, Gross Unrealized Holding Losses	(7,285)	(198)	(170)
Securities available-for-sale, Estimated Fair Value	5,578,048	4,393,029	4,118,863
U.S. Treasury securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale, Amortized Cost Basis, Total			10,083
Securities available-for-sale, Gross Unrealized Holding Gains			40
Securities available-for-sale, Gross Unrealized Holding Losses			(1)
Securities available-for-sale, Estimated Fair Value			10,122
Obligations of State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale, Amortized Cost Basis, Total	2,490,468	2,283,616	1,836,572
Securities available-for-sale, Gross Unrealized Holding Gains	125,612	143,339	113,757
Securities available-for-sale, Gross Unrealized Holding Losses	(993)	(79)	(50)
Securities available-for-sale, Estimated Fair Value	2,615,087	2,426,876	1,950,279
Corporate Bonds and Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale, Amortized Cost Basis, Total	38,297	4,398	4,398
Securities available-for-sale, Gross Unrealized Holding Gains	91	159	171
Securities available-for-sale, Gross Unrealized Holding Losses	(581)		0
Securities available-for-sale, Estimated Fair Value	37,807	4,557	4,569
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale, Amortized Cost Basis, Total	2,471,278	1,421,922	1,517,139
Securities available-for-sale, Gross Unrealized Holding Gains	38,619	50,473	54,652
Securities available-for-sale, Gross Unrealized Holding Losses	(5,711)	(115)	(118)
Securities available-for-sale, Estimated Fair Value	2,504,186	1,472,280	1,571,673
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale, Amortized Cost Basis, Total	405,146	467,243	559,062
Securities available-for-sale, Gross Unrealized Holding Gains	15,822	22,077	23,159
Securities available-for-sale, Gross Unrealized Holding Losses		(4)	(1)
Securities available-for-sale, Estimated Fair Value	$ 420,968	$ 489,316	$ 582,220

Securities - Amortized Cost and

Securities - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Available-for-Sale, Amortized Cost Basis, Due within one year	$ 297,211
Available-for-Sale, Amortized Cost Basis, Due after one year through five years	2,493,104
Available-for-Sale, Amortized Cost Basis, Due after five years through ten years	2,506,074
Available-for-Sale, Amortized Cost Basis, Due after ten years	108,800
Available-for-Sale, Amortized Cost Basis, Total	5,405,189	$ 4,177,179	$ 3,927,254
Available-for-Sale, Estimated Fair Value, Due within one year	301,535
Available-for-Sale, Estimated Fair Value, Due after one year through five years	2,586,178
Available-for-Sale, Estimated Fair Value, Due after five years through ten years	2,581,554
Available-for-Sale, Estimated Fair Value, Due after ten years	108,781
Securities available-for-sale, Estimated Fair Value, Total	$ 5,578,048	$ 4,393,029	$ 4,118,863

Securities - Continuous Unreali

Securities - Continuous Unrealized-Loss Position of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Fair Value	$ 916,767	$ 77,449	$ 40,830
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss	7,279	179	97
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Fair Value	2,478	3,156	6,454
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss	6	19	73
Available-for-sale securities, continuous unrealized loss position, Fair Value	919,245	80,605	47,284
Available-for-sale securities, continuous unrealized loss position, Unrealized Loss	7,285	198	170
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Fair Value			5,055
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss			1
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Fair Value
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss
Available-for-sale securities, continuous unrealized loss position, Fair Value			5,055
Available-for-sale securities, continuous unrealized loss position, Unrealized Loss			1
Obligations of State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Fair Value	170,483	25,214	18,249
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss	992	79	50
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Fair Value
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss
Available-for-sale securities, continuous unrealized loss position, Fair Value	170,483	25,214	18,249
Available-for-sale securities, continuous unrealized loss position, Unrealized Loss	992	79	50
Corporate Bonds and Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Fair Value	33,318
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss	581
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Fair Value
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss
Available-for-sale securities, continuous unrealized loss position, Fair Value	33,318
Available-for-sale securities, continuous unrealized loss position, Unrealized Loss	581
Residential Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Fair Value	712,100	36,017	12,590
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss	5,706	96	45
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Fair Value	2,478	3,156	6,454
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss	6	19	73
Available-for-sale securities, continuous unrealized loss position, Fair Value	714,578	39,173	19,044
Available-for-sale securities, continuous unrealized loss position, Unrealized Loss	5,712	115	118
Commercial Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Fair Value	866	16,218	4,936
Available-for-sale securities, continuous unrealized loss position Less than 12 Months, Unrealized Loss		4	1
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Fair Value
Available-for-sale securities, continuous unrealized loss position 12 Months or Longer, Unrealized Loss
Available-for-sale securities, continuous unrealized loss position, Fair Value	866	16,218	4,936
Available-for-sale securities, continuous unrealized loss position, Unrealized Loss		$ 4	$ 1

Loans Held for Investment and_3

Loans Held for Investment and Allowance for Loan Losses - Loans Held-for-Investment by Class of Financing Receivables (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	$ 5,304,602		$ 5,171,033	$ 5,253,067
Less: Allowance for credit losses	(62,138)	$ (62,974)	(66,534)	(68,947)	$ (60,440)	$ (52,499)
Net loans held for investment	5,242,464		5,104,499	5,184,120
C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	983,103		1,131,382
Less: Allowance for credit losses	(10,186)	(12,323)	(13,609)
Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	179,356		181,325
Less: Allowance for credit losses	(588)	(2,191)	(1,552)
Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	550,928		553,959
Less: Allowance for credit losses	(15,632)	(13,246)	(13,512)
Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	185,288		152,237
Less: Allowance for credit losses	(607)	(1,223)	(1,876)
Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	673,608		617,686
Less: Allowance for credit losses	(10,432)	(9,492)	(8,391)
Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	820,055		746,974
Less: Allowance for credit losses	(10,399)	(9,878)	(12,347)
Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,328,474		1,248,409
Less: Allowance for credit losses	(11,234)	(11,189)	(12,601)
Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	383,764		353,595
Less: Allowance for credit losses	(1,266)	(1,068)	(1,020)
Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	104,814		90,602
Less: Allowance for credit losses	(482)	(379)	(371)
Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,162,459		1,312,707	1,509,454
Less: Allowance for credit losses				(18,572)	(11,773)	(12,122)
Commercial [Member] | C&I [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	983,103		1,131,382
Commercial [Member] | Municipal [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	179,356		181,325
Agriculture [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	95,212		94,864	97,448
Less: Allowance for credit losses	(1,312)	$ (1,985)	(1,255)	(2,544)	(2,154)	(1,206)
Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	3,558,353		3,319,265	3,235,208
Less: Allowance for credit losses				(42,623)	(41,256)	(33,974)
Real Estate [Member] | Construction & Development [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	550,928		553,959
Real Estate [Member] | Farm [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	185,288		152,237
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	673,608		617,686
Real Estate [Member] | Owner Occupied CRE [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	820,055		746,974
Real Estate [Member] | Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	1,328,474		1,248,409
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	488,578		444,197	410,957
Less: Allowance for credit losses				$ (5,208)	$ (5,257)	$ (5,197)
Consumer [Member] | Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	383,764		353,595
Consumer [Member] | Non-Auto [Member]
Loans and Leases Receivable Disclosure [Line Items]
Total Loans	$ 104,814		$ 90,602

Loans Held for Investment and_4

Loans Held for Investment and Allowance for Loan Losses - Non-Accrual Loans, Loans Still Accruing and Past Due 90 Days or More and Restructured Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Receivables [Abstract]
Non-accrual loans	$ 29,786	$ 42,619	$ 39,320
Loans still accruing and past due 90 days or more		113	92
Troubled debt restructured loans still accruing	23	24	25
Total	$ 29,809	$ 42,756	$ 39,437

Loans Held for Investment and_5

Loans Held for Investment and Allowance for Loan Losses - Non-Accrual Loans, Loans Still Accruing and Past Due 90 Days or More and Restructured Loans (Parenthetical) (Detail) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Loans and Leases Receivable Disclosure [Line Items]
Troubled debt restructured loans still accruing	$ 23,000	$ 24,000	$ 25,000
Doubtful [Member]
Loans and Leases Receivable Disclosure [Line Items]
Troubled debt restructured loans still accruing	$ 7,305,000	$ 7,407,000	$ 7,275,000

Loans Held for Investment and_6

Loans Held for Investment and Allowance for Loan Losses - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual, past due 90 days or more and still accruing, restructured loans and foreclosed assets	$ 30,114,000	$ 39,724,000	$ 30,114,000	$ 39,724,000	$ 42,898,000
Additional funds advanced in connection with impaired loans	0		$ 0
Default for purposes of this disclosure is a troubled debt restructured loan			90 days
Commitments to lend additional funds to borrowers with loan that have been modified as TDRs	0		$ 0
Loans held by subsidiaries subject to blanket liens	3,311,924,000		3,311,924,000
Unfunded loan commitments	6,751,000	809,000	6,751,000	809,000	$ 5,486,000
Provision for loan losses	(1,039,000)	$ 8,700,000	(4,468,000)	18,550,000
Provision for credit losses	(1,206,000)		(3,203,000)	$ 18,550,000
Unfunded Loan Commitment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for loan losses	$ 167,000		$ 1,265,000

Loans Held for Investment and_7

Loans Held for Investment and Allowance for Loan Losses - Schedule of Non-Accrual Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 29,786	$ 42,619	$ 39,320
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	3,587	5,015	4,618
Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	3,587	5,015
Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,055	1,076	1,056
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	24,772	36,028	33,170
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,520	3,838
Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,791	7,299
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	6,584	5,243
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	8,976	10,797
Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	5,901	8,851
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	372	500	$ 476
Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	329	407
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 43	$ 93

Loans Held for Investment and_8

Loans Held for Investment and Allowance for Loan Losses - Changes in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	$ 62,974	$ 60,440	$ 66,534	$ 52,499
Provision for loan losses	(1,039)	8,700	(4,468)	18,550
Recoveries	595	701	1,038	1,019
Charge-offs	(392)	(894)	(966)	(3,121)
Ending balance	62,138	68,947	62,138	68,947
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	12,323		13,609
Provision for loan losses	(2,327)		(3,566)
Recoveries	308		531
Charge-offs	(118)		(388)
Ending balance	10,186		10,186
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	2,191		1,552
Provision for loan losses	(1,603)		(964)
Recoveries	0		0
Charge-offs	0		0
Ending balance	588		588
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	13,246		13,512
Provision for loan losses	2,386		2,118
Recoveries	0		2
Charge-offs	0		0
Ending balance	15,632		15,632
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,223		1,876
Provision for loan losses	(617)		(1,279)
Recoveries	1		10
Charge-offs	0		0
Ending balance	607		607
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	9,492		8,391
Provision for loan losses	901		1,953
Recoveries	39		94
Charge-offs	0		(6)
Ending balance	10,432		10,432
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	9,878		12,347
Provision for loan losses	517		(1,950)
Recoveries	4		10
Charge-offs	0		(8)
Ending balance	10,399		10,399
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	11,189		12,601
Provision for loan losses	26		(1,358)
Recoveries	64		83
Charge-offs	(45)		(92)
Ending balance	11,234		11,234
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,068		1,020
Provision for loan losses	257		398
Recoveries	103		176
Charge-offs	(162)		(328)
Ending balance	1,266		1,266
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	379		371
Provision for loan losses	88		126
Recoveries	61		108
Charge-offs	(46)		(123)
Ending balance	482		482
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		11,773		12,122
Provision for loan losses		6,820		7,615
Recoveries		540		690
Charge-offs		(561)		(1,855)
Ending balance		18,572		18,572
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance	1,985	2,154	1,255	1,206
Provision for loan losses	(667)	361	54	1,310
Recoveries	15	29	24	30
Charge-offs	(21)	0	(21)	(2)
Ending balance	$ 1,312	2,544	$ 1,312	2,544
Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		41,256		33,974
Provision for loan losses		1,469		9,390
Recoveries		59		135
Charge-offs		(161)		(876)
Ending balance		42,623		42,623
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance		5,257		5,197
Provision for loan losses		50		235
Recoveries		73		164
Charge-offs		(172)		(388)
Ending balance		$ 5,208		$ 5,208

Loans Held for Investment and_9

Loans Held for Investment and Allowance for Loan Losses - Schedule of loans that are individually evaluated for credit losses (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	$ 53,588	$ 53,588
Recorded Investment With No Allowance	21,638	21,638
Recorded Investment With Allowance	17,682	17,682
Total Recorded Investment	39,320	39,320	$ 174,994	$ 197,451
Related Allowance	3,046	3,046	17,186	20,637
Average Recorded Investment	41,410	42,681
Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			20,209	21,439
Recorded Investment With Allowance			9,577	21,180
Related Allowance			1,669	3,419
Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			145,208	154,832
Related Allowance			15,517	17,218
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	6,013	6,013
Recorded Investment With No Allowance	739	739
Recorded Investment With Allowance	3,879	3,879
Total Recorded Investment	4,618	4,618	25,310	40,083
Related Allowance	1,250	1,250	4,863	6,826
Average Recorded Investment	23,572	24,270
Commercial [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			1,091	1,544
Recorded Investment With Allowance			2,496	3,471
Related Allowance			723	799
Commercial [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			21,723	35,068
Related Allowance			4,140	6,027
Commercial [Member] | C&I [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			24,425	30,644
Related Allowance			4,588	5,391
Commercial [Member] | C&I [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			1,091	1,544
Recorded Investment With Allowance			2,496	3,471
Related Allowance			723	799
Commercial [Member] | C&I [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			20,838	25,629
Related Allowance			3,865	4,592
Commercial [Member] | Municipal [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			885	9,439
Related Allowance			275	1,435
Commercial [Member] | Municipal [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			885	9,439
Related Allowance			275	1,435
Agriculture [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	1,287	1,287
Recorded Investment With No Allowance	529	529
Recorded Investment With Allowance	527	527
Total Recorded Investment	1,056	1,056	6,250	6,648
Related Allowance	83	83	1,255	982
Average Recorded Investment	179	219
Agriculture [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			328	470
Recorded Investment With Allowance			727	606
Related Allowance			171	96
Agriculture [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			5,195	5,572
Related Allowance			1,084	886
Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	45,703	45,703
Recorded Investment With No Allowance	20,370	20,370
Recorded Investment With Allowance	12,800	12,800
Total Recorded Investment	33,170	33,170	141,367	148,256
Related Allowance	1,711	1,711	11,061	12,821
Average Recorded Investment	17,107	17,586
Real Estate [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			18,790	19,425
Recorded Investment With Allowance			5,982	16,602
Related Allowance			774	2,522
Real Estate [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			116,595	112,229
Related Allowance			10,287	10,299
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			10,721	15,205
Related Allowance			1,099	652
Real Estate [Member] | Construction & Development [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			1,282	1,176
Recorded Investment With Allowance			238	2,661
Related Allowance			24	35
Real Estate [Member] | Construction & Development [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			9,201	11,368
Related Allowance			1,075	617
Real Estate [Member] | Farm [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			4,536	10,648
Related Allowance			9	1,312
Real Estate [Member] | Farm [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			1,697	2,614
Recorded Investment With Allowance			94	4,685
Related Allowance			0	654
Real Estate [Member] | Farm [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			2,745	3,349
Related Allowance			9	658
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			40,291	22,626
Related Allowance			4,200	1,921
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			6,444	4,009
Recorded Investment With Allowance			140	1,234
Related Allowance			15	500
Real Estate [Member] | Non-Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			33,707	17,383
Related Allowance			4,185	1,421
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			51,808	62,730
Related Allowance			3,144	5,829
Real Estate [Member] | Owner Occupied CRE [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			5,605	7,279
Recorded Investment With Allowance			3,371	3,518
Related Allowance			544	657
Real Estate [Member] | Owner Occupied CRE [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			42,832	51,933
Related Allowance			2,600	5,172
Real Estate [Member] | Residential [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			34,011	37,047
Related Allowance			2,609	3,107
Real Estate [Member] | Residential [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With No Allowance			3,762	4,347
Recorded Investment With Allowance			2,139	4,504
Related Allowance			191	676
Real Estate [Member] | Residential [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			28,110	28,196
Related Allowance			2,418	2,431
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	585	585
Recorded Investment With Allowance	476	476
Total Recorded Investment	476	476	2,067	2,464
Related Allowance	2	2	7	8
Average Recorded Investment	$ 552	$ 606
Consumer [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance			372	501
Related Allowance			1	2
Consumer [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			1,695	1,963
Related Allowance			6	6
Consumer [Member] | Auto [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			1,671	1,930
Related Allowance			5	6
Consumer [Member] | Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance			329	407
Related Allowance			1	1
Consumer [Member] | Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			1,342	1,523
Related Allowance			4	5
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			396	534
Related Allowance			2	2
Consumer [Member] | Non-Auto [Member] | Collateral Pledged [Member]
Financing Receivable, Impaired [Line Items]
Recorded Investment With Allowance			43	94
Related Allowance				1
Consumer [Member] | Non-Auto [Member] | Uncollateralized [Member]
Financing Receivable, Impaired [Line Items]
Total Recorded Investment			353	440
Related Allowance			$ 2	$ 1

Loans Held for Investment an_10

Loans Held for Investment and Allowance for Loan Losses - Schedule of Allowance for Loan Losses by Portfolio Segment (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	$ 17,186		$ 20,637	$ 3,046
Loans collectively evaluated for credit losses	44,952		45,897	65,901
Total allowance for loan losses	62,138	$ 62,974	66,534	68,947	$ 60,440	$ 52,499
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	4,588		5,391
Loans collectively evaluated for credit losses	5,598		8,218
Total allowance for loan losses	10,186	12,323	13,609
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	275		1,435
Loans collectively evaluated for credit losses	313		117
Total allowance for loan losses	588	2,191	1,552
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,255		982
Loans collectively evaluated for credit losses	57		273
Total allowance for loan losses	1,312		1,255
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	1,099		652
Loans collectively evaluated for credit losses	14,533		12,860
Total allowance for loan losses	15,632	13,246	13,512
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	9		1,312
Loans collectively evaluated for credit losses	598		564
Total allowance for loan losses	607	1,223	1,876
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	4,200		1,921
Loans collectively evaluated for credit losses	6,232		6,470
Total allowance for loan losses	10,432	9,492	8,391
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	3,144		5,829
Loans collectively evaluated for credit losses	7,255		6,518
Total allowance for loan losses	10,399	9,878	12,347
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2,609		3,107
Loans collectively evaluated for credit losses	8,625		9,494
Total allowance for loan losses	11,234	11,189	12,601
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	5		6
Loans collectively evaluated for credit losses	1,261		1,014
Total allowance for loan losses	1,266	1,068	1,020
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses	2		2
Loans collectively evaluated for credit losses	480		369
Total allowance for loan losses	482	379	371
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses				1,250
Loans collectively evaluated for credit losses				17,322
Total allowance for loan losses				18,572	11,773	12,122
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses				83
Loans collectively evaluated for credit losses				2,461
Total allowance for loan losses	$ 1,312	$ 1,985	$ 1,255	2,544	2,154	1,206
Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses				1,711
Loans collectively evaluated for credit losses				40,912
Total allowance for loan losses				42,623	41,256	33,974
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for credit losses				2
Loans collectively evaluated for credit losses				5,206
Total allowance for loan losses				$ 5,208	$ 5,257	$ 5,197

Loans Held for Investment an_11

Loans Held for Investment and Allowance for Loan Losses - Schedule of Investment in Loans Related to Balance in Allowance for Loan Losses on Basis of Company's Impairment Methodology (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	$ 174,994	$ 197,451	$ 39,320
Loan collectively evaluated for impairment	5,129,608	4,973,582	5,213,747
Total	5,304,602	5,171,033	5,253,067
C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	24,425	30,644
Loan collectively evaluated for impairment	958,678	1,100,738
Total	983,103	1,131,382
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	885	9,439
Loan collectively evaluated for impairment	178,471	171,886
Total	179,356	181,325
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	6,250	6,648
Loan collectively evaluated for impairment	88,962	88,216
Total	95,212	94,864
Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	10,721	15,205
Loan collectively evaluated for impairment	540,207	538,754
Total	550,928	553,959
Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	4,536	10,648
Loan collectively evaluated for impairment	180,752	141,589
Total	185,288	152,237
Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	40,291	22,626
Loan collectively evaluated for impairment	633,317	595,060
Total	673,608	617,686
Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	51,808	62,730
Loan collectively evaluated for impairment	768,247	684,244
Total	820,055	746,974
Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	34,011	37,047
Loan collectively evaluated for impairment	1,294,463	1,211,362
Total	1,328,474	1,248,409
Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	1,671	1,930
Loan collectively evaluated for impairment	382,093	351,665
Total	383,764	353,595
Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment	396	534
Loan collectively evaluated for impairment	104,418	90,068
Total	104,814	90,602
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment			4,618
Loan collectively evaluated for impairment			1,504,836
Total	1,162,459	1,312,707	1,509,454
Commercial [Member] | C&I [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	983,103	1,131,382
Commercial [Member] | Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	179,356	181,325
Agriculture [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment			1,056
Loan collectively evaluated for impairment			96,392
Total	95,212	94,864	97,448
Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment			33,170
Loan collectively evaluated for impairment			3,202,038
Total	3,558,353	3,319,265	3,235,208
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	550,928	553,959
Real Estate [Member] | Farm [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	185,288	152,237
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	673,608	617,686
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	820,055	746,974
Real Estate [Member] | Residential [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	1,328,474	1,248,409
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment			476
Loan collectively evaluated for impairment			410,481
Total	488,578	444,197	$ 410,957
Consumer [Member] | Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	383,764	353,595
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total	$ 104,814	$ 90,602

Loans Held-for-Investment and A

Loans Held-for-Investment and Allowance for Loan Losses - Schedule of Company's Internal Ratings of its Loans Held-for-Investment, Including The Year of Origination, by Portfolio Segments (Detail) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	$ 1,503	$ 2,418
2020-2019	1,535	832
2019-2018	652	571
2018-2017	448	350
2017-2016	285	279
Prior	779	619
Revolving Loans Amort Cost Basis	103	102
Total	5,305	5,171
C&I [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	493	895
2020-2019	324	107
2019-2018	74	74
2018-2017	50	29
2017-2016	23	10
Prior	19	16
Total	983	1,131
Municipal [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	23	28
2020-2019	23	19
2019-2018	8	29
2018-2017	22	19
2017-2016	18	14
Prior	85	72
Total	179	181
Agriculture [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	30	63
2020-2019	39	19
2019-2018	15	9
2018-2017	7	3
2017-2016	4	1
Prior	1
Total	96	95
Construction & Development [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	223	377
2020-2019	241	102
2019-2018	43	36
2018-2017	18	22
2017-2016	9	7
Prior	17	10
Total	551	554
Farm [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	59	64
2020-2019	55	23
2019-2018	17	18
2018-2017	13	12
2017-2016	9	11
Prior	32	24
Total	185	152
Non-Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	103	198
2020-2019	172	119
2019-2018	120	94
2018-2017	81	52
2017-2016	50	56
Prior	148	99
Total	674	618
Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	146	186
2020-2019	183	141
2019-2018	135	127
2018-2017	118	83
2017-2016	70	67
Prior	168	143
Total	820	747
Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	268	381
2020-2019	324	176
2019-2018	149	138
2018-2017	108	105
2017-2016	87	103
Prior	295	250
Revolving Loans Amort Cost Basis	97	95
Total	1,328	1,248
Auto [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	118	178
2020-2019	141	105
2019-2018	77	39
2018-2017	26	21
2017-2016	13	9
Prior	9	2
Total	384	354
Non-Auto [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	40	48
2020-2019	33	21
2019-2018	14	7
2018-2017	5	4
2017-2016	2	1
Prior	5	3
Revolving Loans Amort Cost Basis	6	7
Total	105	91
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	1,479	2,356
2020-2019	1,501	804
2019-2018	618	540
2018-2017	424	320
2017-2016	264	273
Prior	743	580
Revolving Loans Amort Cost Basis	102	100
Total	5,131	4,973
Pass [Member] | C&I [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	485	874
2020-2019	316	101
2019-2018	71	70
2018-2017	46	28
2017-2016	22	10
Prior	19	16
Total	959	1,099
Pass [Member] | Municipal [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	23	26
2020-2019	23	19
2019-2018	8	29
2018-2017	22	14
2017-2016	18	13
Prior	84	71
Total	178	172
Pass [Member] | Agriculture [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	30	57
2020-2019	34	19
2019-2018	15	9
2018-2017	7	3
2017-2016	3	1
Prior	1
Total	90	89
Pass [Member] | Construction & Development [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	220	371
2020-2019	237	97
2019-2018	39	36
2018-2017	18	19
2017-2016	9	7
Prior	17	9
Total	540	539
Pass [Member] | Farm [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	59	57
2020-2019	53	22
2019-2018	17	18
2018-2017	12	11
2017-2016	9	11
Prior	31	23
Total	181	142
Pass [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	101	197
2020-2019	171	117
2019-2018	104	93
2018-2017	80	44
2017-2016	40	55
Prior	138	88
Total	634	594
Pass [Member] | Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	137	176
2020-2019	178	132
2019-2018	129	105
2018-2017	103	75
2017-2016	64	65
Prior	157	132
Total	768	685
Pass [Member] | Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	266	373
2020-2019	316	172
2019-2018	145	134
2018-2017	105	101
2017-2016	84	101
Prior	282	237
Revolving Loans Amort Cost Basis	96	93
Total	1,294	1,211
Pass [Member] | Auto [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	118	177
2020-2019	140	104
2019-2018	76	39
2018-2017	26	21
2017-2016	13	9
Prior	9	2
Total	382	352
Pass [Member] | Non-Auto [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	40	48
2020-2019	33	21
2019-2018	14	7
2018-2017	5	4
2017-2016	2	1
Prior	5	2
Revolving Loans Amort Cost Basis	6	7
Total	105	90
Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	6	20
2020-2019	10	12
2019-2018	16	4
2018-2017	4	14
2017-2016	13	3
Prior	7	4
Total	56	57
Special Mention [Member] | C&I [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	4	9
2020-2019	2	2
2019-2018	1
2018-2017	1	1
2017-2016	1
Total	9	12
Special Mention [Member] | Construction & Development [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	1	2
2020-2019	2	4
Total	3	6
Special Mention [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020		1
2020-2019	1
2019-2018	13	1
2018-2017	1	8
2017-2016	7	1
Prior	3
Total	25	11
Special Mention [Member] | Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	1	5
2020-2019	2	5
2019-2018	1	2
2018-2017	1	4
2017-2016	4	1
Prior	1	1
Total	10	18
Special Mention [Member] | Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020		3
2020-2019	3	1
2019-2018	1	1
2018-2017	1	1
2017-2016	1	1
Prior	3	3
Total	9	10
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	18	42
2020-2019	24	16
2019-2018	18	27
2018-2017	20	16
2017-2016	8	3
Prior	29	35
Revolving Loans Amort Cost Basis	1	2
Total	118	141
Substandard [Member] | C&I [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	4	12
2020-2019	6	4
2019-2018	2	4
2018-2017	3
Total	15	20
Substandard [Member] | Municipal [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020		2
2018-2017		5
2017-2016		1
Prior	1	1
Total	1	9
Substandard [Member] | Agriculture [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020		6
2020-2019	5
2017-2016	1
Total	6	6
Substandard [Member] | Construction & Development [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	2	4
2020-2019	2	1
2019-2018	4
2018-2017	0	3
Prior		1
Total	8	9
Substandard [Member] | Farm [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020		7
2020-2019	2	1
2018-2017	1	1
Prior	1	1
Total	4	10
Substandard [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	2
2020-2019		2
2019-2018	3
2017-2016	3
Prior	7	11
Total	15	13
Substandard [Member] | Owner Occupied CRE [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	8	5
2020-2019	3	4
2019-2018	5	20
2018-2017	14	4
2017-2016	2	1
Prior	10	10
Total	42	44
Substandard [Member] | Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020	2	5
2020-2019	5	3
2019-2018	3	3
2018-2017	2	3
2017-2016	2	1
Prior	10	10
Revolving Loans Amort Cost Basis	1	2
Total	25	27
Substandard [Member] | Auto [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
2021-2020		1
2020-2019	1	1
2019-2018	1
Total	$ 2	2
Substandard [Member] | Non-Auto [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Prior		1
Total		$ 1

Loans Held for Investment an_12

Loans Held for Investment and Allowance for Loan Losses - Schedule of Internal Ratings of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan	$ 5,304,602	$ 5,171,033	$ 5,253,067
Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan	1,162,459	1,312,707	1,509,454
Agriculture [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan	95,212	94,864	97,448
Internal ratings of loan			98,000
Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan	3,558,353	3,319,265	3,235,208
Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan	$ 488,578	$ 444,197	410,957
Pass [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			5,052,000
Pass [Member] | Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			1,465,000
Pass [Member] | Agriculture [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			91,000
Pass [Member] | Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			3,087,000
Pass [Member] | Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			409,000
Special Mention [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			64,000
Special Mention [Member] | Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			9,000
Special Mention [Member] | Agriculture [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			5,000
Special Mention [Member] | Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			50,000
Substandard [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			137,000
Substandard [Member] | Commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			35,000
Substandard [Member] | Agriculture [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			2,000
Substandard [Member] | Real Estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			98,000
Substandard [Member] | Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Internal ratings of loan			$ 2,000

Loans Held for Investment an_13

Loans Held for Investment and Allowance for Loan Losses - Schedule of Past Due Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 18,395	$ 22,292	$ 21,373
Total Current	5,286,207	5,148,741	5,231,694
Total Loans	5,304,602	5,171,033	5,253,067
Total 90 Days Past Due Still Accruing		113	92
C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	983,103	1,131,382
Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	179,356	181,325
Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	550,928	553,959
Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	185,288	152,237
Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	673,608	617,686
Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	820,055	746,974
Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,328,474	1,248,409
Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	383,764	353,595
Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	104,814	90,602
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,025	4,629	5,166
Total Current	1,156,434	1,308,078	1,504,288
Total Loans	1,162,459	1,312,707	1,509,454
Total 90 Days Past Due Still Accruing		21
Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,369	4,629
Total Current	978,734	1,126,753
Total Loans	983,103	1,131,382
Total 90 Days Past Due Still Accruing		21
Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,656
Total Current	177,700	181,325
Total Loans	179,356	181,325
Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	238	288	1,095
Total Current	94,974	94,576	96,353
Total Loans	95,212	94,864	97,448
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11,667	16,353	14,514
Total Current	3,546,686	3,302,912	3,220,694
Total Loans	3,558,353	3,319,265	3,235,208
Total 90 Days Past Due Still Accruing		33
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,135	4,819
Total Current	548,793	549,140
Total Loans	550,928	553,959
Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,138	708
Total Current	184,150	151,529
Total Loans	185,288	152,237
Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,057	613
Total Current	672,551	617,073
Total Loans	673,608	617,686
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	918	1,848
Total Current	819,137	745,126
Total Loans	820,055	746,974
Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,419	8,365
Total Current	1,322,055	1,240,044
Total Loans	1,328,474	1,248,409
Total 90 Days Past Due Still Accruing		33
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	465	1,022	598
Total Current	488,113	443,175	410,359
Total Loans	488,578	444,197	410,957
Total 90 Days Past Due Still Accruing		59	92
Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	410	784
Total Current	383,354	352,811
Total Loans	383,764	353,595
Total 90 Days Past Due Still Accruing		59
Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	55	238
Total Current	104,759	90,364
Total Loans	104,814	90,602
15-59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	15,705	20,166	19,731
15-59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,088	3,647	4,563
15-59 Days Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,432	3,647
15-59 Days Past Due [Member] | Commercial [Member] | Municipal [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,656
15-59 Days Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	193	193	1,080
15-59 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10,050	15,561	13,678
15-59 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,973	4,775
15-59 Days Past Due [Member] | Real Estate [Member] | Farm [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,138	708
15-59 Days Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	896	613
15-59 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	97	1,393
15-59 Days Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,946	8,072
15-59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	374	765	410
15-59 Days Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	330	551
15-59 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	44	214
60-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,138	1,067	682
60-89 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	707	406	474
60-89 Days Past Due [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	707	406
60-89 Days Past Due [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10	95	15
60-89 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,355	384	110
60-89 Days Past Due [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		44
60-89 Days Past Due [Member] | Real Estate [Member] | Non-Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	161
60-89 Days Past Due [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	821	322
60-89 Days Past Due [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	373	18
60-89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	66	182	83
60-89 Days Past Due [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	55	158
60-89 Days Past Due [Member] | Consumer [Member] | Non-Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11	24
Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	552	1,059	960
Greater than 90 Days [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	230	576	129
Greater than 90 Days [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	230	576
Greater than 90 Days [Member] | Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	35
Greater than 90 Days [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	262	408	726
Greater than 90 Days [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	162
Greater than 90 Days [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		133
Greater than 90 Days [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	100	275
Greater than 90 Days [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	25	75	$ 105
Greater than 90 Days [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 25	$ 75

Loans Held for Investment an_14

Loans Held for Investment and Allowance for Loan Losses - Schedule of Loans Modified and Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)SecurityLoan	Jun. 30, 2020USD ($)SecurityLoan	Jun. 30, 2021USD ($)SecurityLoan	Jun. 30, 2020USD ($)SecurityLoan
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	8	5	13	12
Pre-Modification Recorded Investment	$ 1,304	$ 319	$ 2,150	$ 755
Post-Modification Recorded Investment	$ 1,304	$ 319	$ 2,150	$ 755
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	2	4	4	9
Pre-Modification Recorded Investment	$ 212	$ 196	$ 361	$ 484
Post-Modification Recorded Investment	$ 212	$ 196	$ 361	$ 484
Commercial [Member] | Commercial – C&I [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	2		4
Pre-Modification Recorded Investment	$ 212		$ 361
Post-Modification Recorded Investment	$ 212		$ 361
Agriculture [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	1		1	1
Pre-Modification Recorded Investment	$ 68		$ 68	$ 134
Post-Modification Recorded Investment	$ 68		$ 68	$ 134
Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	4	1	7	1
Pre-Modification Recorded Investment	$ 993	$ 123	$ 1,690	$ 123
Post-Modification Recorded Investment	$ 993	$ 123	$ 1,690	$ 123
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	1		1
Pre-Modification Recorded Investment	$ 200		$ 200
Post-Modification Recorded Investment	$ 200		$ 200
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	2		3
Pre-Modification Recorded Investment	$ 548		$ 1,047
Post-Modification Recorded Investment	$ 548		$ 1,047
Real Estate [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	1		3
Pre-Modification Recorded Investment	$ 245		$ 443
Post-Modification Recorded Investment	$ 245		$ 443
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	1		1	1
Pre-Modification Recorded Investment	$ 31		$ 31	$ 14
Post-Modification Recorded Investment	$ 31		$ 31	$ 14
Consumer [Member] | Auto [Member]
Financing Receivable, Modifications [Line Items]
Number | SecurityLoan	1		1
Pre-Modification Recorded Investment	$ 31		$ 31
Post-Modification Recorded Investment	$ 31		$ 31

Loans Held for Investment an_15

Loans Held for Investment and Allowance for Loan Losses - Schedule of How Loans Were Modified as Troubled Debt Restructured Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	$ 1,304	$ 319	$ 2,150	$ 755
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	212	196	361	484
Commercial [Member] | C&I [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	212		361
Agriculture [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	68		68	134
Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	993	123	1,690	123
Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	200		200
Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	548		1,047
Real Estate [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	245		443
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	31		31	14
Consumer [Member] | Auto [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	31		31
Maturity Extended [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	725		725	408
Maturity Extended [Member] | Commercial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	212		212	260
Maturity Extended [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	212		212
Maturity Extended [Member] | Agriculture [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	68		68	134
Maturity Extended [Member] | Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	445		445
Maturity Extended [Member] | Real Estate [Member] | Construction & Development [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	200		200
Maturity Extended [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	245		245
Maturity Extended [Member] | Consumer [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans				14
Combined Rate and Maturity [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	579	319	1,425	347
Combined Rate and Maturity [Member] | Commercial [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans		196	149	224
Combined Rate and Maturity [Member] | Commercial [Member] | C&I [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans			149
Combined Rate and Maturity [Member] | Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	548	$ 123	1,245	$ 123
Combined Rate and Maturity [Member] | Real Estate [Member] | Owner Occupied CRE [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	548		1,047
Combined Rate and Maturity [Member] | Real Estate [Member] | Residential [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans			198
Combined Rate and Maturity [Member] | Consumer [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	31		31
Combined Rate and Maturity [Member] | Consumer [Member] | Auto [Member]
Financing Receivable, Modifications [Line Items]
Troubled Debt Restructured Loans	$ 31		$ 31

Loans Held for Sale - Additiona

Loans Held for Sale - Additional Information (Detail) - USD ($)	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Loans Receivables Held For Sale Net [Abstract]
Loans held for sale	$ 61,802,000	$ 83,969,000	$ 66,370,000
Loans held-for-sale at the lower of cost or fair value	$ 5,545,000	$ 4,384,000	$ 3,077,000

Derivative Financial Instrume_3

Derivative Financial Instruments - Summary of Outstanding Notional Balances and Fair Values of Outstanding Derivative Positions (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
IRLCs [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Outstanding Notional Balance	$ 143,879	$ 202,906	$ 190,431
Asset Derivative Fair Value	2,670	4,618	5,037
Liability Derivative Fair Value	0	0	0
Forward Mortgage-Backed Securities Trades [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Outstanding Notional Balance	165,000	198,000	201,500
Asset Derivative Fair Value	0	0	0
Liability Derivative Fair Value	$ 376	$ 1,560	$ 1,099

Borrowings - Schedule of Borrow

Borrowings - Schedule of Borrowings (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Debt Disclosure [Abstract]
Securities sold under agreements with customers to repurchase	$ 531,469	$ 412,743	$ 444,249
Federal funds purchased	18,500	17,350	4,975
Advances from Federal Home Loan Bank of Dallas	0		0
Total	$ 549,969	$ 430,093	$ 449,224

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Debt Disclosure [Abstract]
Revolving line of credit, permitted	$ 25,000,000
Line of credit	$ 0	$ 0	$ 0
Line of credit, maturity date	Jun. 30, 2021

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Taxes [Line Items]
Federal statutory tax rate			21.00%
Income tax expense	$ 11,075	$ 10,663	$ 22,129	$ 17,898
Effective tax rates on pre-tax income	16.42%	16.63%	16.34%	16.48%

Stock Option Plan and Restric_3

Stock Option Plan and Restricted Stock Plan - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Apr. 27, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options granted			20.00%
Duration of options granted, years			10 years
Stock options outstanding, exercise price range, lower			$ 7.87
Stock options outstanding, exercise price range, upper			$ 34.55
Total unrecognized compensation cost related to nonvested share-based compensation arrangements granted under the Plan	$ 3,374,000		$ 3,374,000
Weighted-average period of unrecognized compensation cost recognition, years			1 year 8 months 8 days
Total fair value of shares vested			$ 1,246,000	$ 791,000
Stock compensation expense	372,000	$ 349,000	691,000	689,000
Dividends Payable	$ 21,357,000	18,462,000	$ 21,357,000	18,462,000		$ 18,484,000
Two Thousand Twenty One Omnibus Stock and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of stock for issuance under the plan	2,487,890		2,487,890		2,500,000
Other Liabilities [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividends Payable	$ 59,000	55,000	$ 59,000	55,000		$ 49,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to nonvested share-based compensation arrangements granted under the Plan	1,845,000	2,441,000	$ 1,845,000	$ 2,441,000
Weighted-average period of unrecognized compensation cost recognition, years			1 year 3 months 29 days	1 year 9 months 3 days
Total fair value of shares vested			$ 883,000	$ 918,000
Restricted Stock [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	150,000	160,000	300,000	335,000
Restricted Stock [Member] | Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expense	$ 289,000	$ 322,000	$ 579,000	$ 597,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of stock for issuance under the plan					2,500,000
Restricted shares vesting period			2 years

Stock Option Plan and Restric_4

Stock Option Plan and Restricted Stock Plan - Schedule of Analysis of Stock Option Activity (Detail)	6 Months Ended
	Jun. 30, 2021$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding, beginning of year, Shares | shares	1,833,057
Exercised, Shares | shares	(165,371)
Cancelled, Shares | shares	(17,600)
Outstanding, end of year, Shares | shares	1,650,086
Exercisable at end of year, Shares | shares	938,436
Outstanding, beginning of year, Weighted-Average Ex. Price | $ / shares	$ 20.85
Exercised, Weighted-Average Ex. Price | $ / shares	15.89
Cancelled, Weighted-Average Ex. Price | $ / shares	25.61
Outstanding, end of year, Weighted-Average Ex. Price | $ / shares	21.29
Exercisable at end of year, Weighted-Average Ex. Price | $ / shares	$ 19.04

Stock Option Plan and Restric_5

Stock Option Plan and Restricted Stock Plan - Summary of Vested and Unvested Restricted Stock Outstanding (Detail) - $ / shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Balance at beginning of period	95,888	105,309
Grants	12,110	32,149
Vesting	(31,081)	(30,276)
Forfeited/expired	(1,027)	(239)
Balance at end of period	75,890	106,943
Balance at beginning of period	$ 29.89	$ 29.93
Grants	49.58	28.55
Vesting	28.42	30.27
Forfeited/expired	34.55	29.70
Balance at end of period	$ 33.57	$ 29.42

Fair Value Disclosures - Additi

Fair Value Disclosures - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)Loans	Jun. 30, 2020USD ($)Loans	Dec. 31, 2020USD ($)Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets transfer between Level 2 and Level 3	$ 0	$ 0	$ 0	$ 0	$ 0
Other real estate owned, total	283,000	202,000	$ 283,000	$ 202,000	$ 119,000
Residential Mortgage [Member] | Greater than 90 Days [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of loans held-for-sale | Loans			0	0	0
Recognized credit losses	$ 0	$ 0	$ 0	$ 0
Minimum [Member] | Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt discounts, percentage	5		5
Maximum [Member] | Measurement Input, Discount Rate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt discounts, percentage	25		25

Fair Value Disclosures - Financ

Fair Value Disclosures - Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	$ 5,578,048	$ 4,393,029	$ 4,118,863
Loans held-for-sale	61,802	83,969	66,370
U.S. Treasury Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value			10,122
Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	2,615,087	2,426,876	1,950,279
Residential Mortgage-Backed Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	2,504,186	1,472,280	1,571,673
Commercial Mortgage-Backed Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	420,968	489,316	582,220
IRLCs [Member]
Available-for-sale investment securities:
Asset Derivative Fair Value	2,670	4,618	5,037
Forward mortgage-backed securities trades	0	0	0
Forward Mortgage-Backed Securities Trades [Member]
Available-for-sale investment securities:
Asset Derivative Fair Value	0	0	0
Forward mortgage-backed securities trades	376	1,560	1,099
Fair Value, Measurements, Recurring [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	5,578,048	4,393,029	4,118,863
Loans held-for-sale	56,257	79,585	63,293
Fair Value, Measurements, Recurring [Member] | U.S. Treasury Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value			10,122
Fair Value, Measurements, Recurring [Member] | Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	2,615,087	2,426,876	1,950,279
Fair Value, Measurements, Recurring [Member] | Residential Mortgage-Backed Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	2,504,186	1,472,280	1,571,673
Fair Value, Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	420,968	489,316	582,220
Fair Value, Measurements, Recurring [Member] | IRLCs [Member]
Available-for-sale investment securities:
Asset Derivative Fair Value	2,670	4,618	5,037
Fair Value, Measurements, Recurring [Member] | Forward Mortgage-Backed Securities Trades [Member]
Available-for-sale investment securities:
Forward mortgage-backed securities trades	(376)	(1,560)	(1,099)
Fair Value, Measurements, Recurring [Member] | Corporate Bonds [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	33,318
Fair Value, Measurements, Recurring [Member] | Other Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	4,489	4,557	4,569
Fair Value, Measurements, Recurring [Member] | Level 1 Inputs [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	4,489	4,557	14,691
Fair Value, Measurements, Recurring [Member] | Level 1 Inputs [Member] | U.S. Treasury Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value			10,122
Fair Value, Measurements, Recurring [Member] | Level 1 Inputs [Member] | Other Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	4,489	4,557	4,569
Fair Value, Measurements, Recurring [Member] | Level 2 Inputs [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	5,573,559	4,388,472	4,104,172
Loans held-for-sale	56,257	79,585	63,293
Fair Value, Measurements, Recurring [Member] | Level 2 Inputs [Member] | Obligations of State and Political Subdivisions [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	2,615,087	2,426,876	1,950,279
Fair Value, Measurements, Recurring [Member] | Level 2 Inputs [Member] | Residential Mortgage-Backed Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	2,504,186	1,472,280	1,571,673
Fair Value, Measurements, Recurring [Member] | Level 2 Inputs [Member] | Commercial Mortgage-Backed Securities [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	420,968	489,316	582,220
Fair Value, Measurements, Recurring [Member] | Level 2 Inputs [Member] | IRLCs [Member]
Available-for-sale investment securities:
Asset Derivative Fair Value	2,670	4,618	5,037
Fair Value, Measurements, Recurring [Member] | Level 2 Inputs [Member] | Forward Mortgage-Backed Securities Trades [Member]
Available-for-sale investment securities:
Forward mortgage-backed securities trades	(376)	$ (1,560)	$ (1,099)
Fair Value, Measurements, Recurring [Member] | Level 2 Inputs [Member] | Corporate Bonds [Member]
Available-for-sale investment securities:
Available-for-sale investment securities, Total Fair Value	$ 33,318

Fair Value Disclosures - Summar

Fair Value Disclosures - Summary of Loans Held-for-Sale at Fair Value (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Fair Value Measurements Loans Held For Sale [Abstract]
Unpaid principal balance on loans held-for-sale	$ 54,542	$ 76,602	$ 60,432
Net unrealized gains on loans held-for-sale	1,715	2,983	2,861
Loans held-for-sale at fair value	$ 56,257	$ 79,585	$ 63,293

Fair Value Disclosures - Schedu

Fair Value Disclosures - Schedule of Gain Loss on Sale of Mortgage Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Schedule Of Gain Loss On Sale Of Mortgage Loans [Abstract]
Realized gain on sale and fees on mortgage loans	$ 9,465	$ 7,637	$ 20,195	$ 10,103
Change in fair value on loans held-for-sale and IRLCs	2,008	3,937	(3,193)	6,292
Change in forward mortgage-backed securities trades	(3,182)	2,102	1,183	(946)
Total gain on sale of mortgage loans	$ 8,291	$ 13,676	$ 18,185	$ 15,449

Fair Value Disclosures - Sche_2

Fair Value Disclosures - Schedule of Estimated Fair Values and Carrying Values of All Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	$ 190,061	$ 211,113	$ 188,373
Interest-bearing demand deposits in banks	654,531	517,971	196,426
Available-for-sale securities	5,578,048	4,393,029	4,118,863
Loans held-for-investment, net of allowance for credit losses	5,242,464	5,104,499	5,184,120
Loans held for sale	61,802	83,969	66,370
Borrowings	549,969	430,093	449,224
IRLCs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset Derivative Fair Value	2,670	4,618	5,037
Forward mortgage-backed securities trades liability	0	0	0
Forward Mortgage-Backed Securities Trades [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset Derivative Fair Value	0	0	0
Forward mortgage-backed securities trades liability	376	1,560	1,099
Carrying Value [Member] | Level 1 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	190,061	211,113	188,373
Interest-bearing demand deposits in banks	654,531	517,971	196,426
Deposits with no stated maturities	9,311,213	8,200,275	7,691,520
Carrying Value [Member] | Level 1 Inputs [Member] | Forward Mortgage-Backed Securities Trades [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Forward mortgage-backed securities trades liability	(376)	(1,560)	(1,099)
Carrying Value [Member] | Level 2 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale	61,802	83,969	66,370
Accrued interest receivable	54,128	53,433	45,801
Deposits with stated maturities	470,481	475,542	466,122
Borrowings	549,969	430,093	449,224
Accrued interest payable	316	377	541
Carrying Value [Member] | Level 2 Inputs [Member] | IRLCs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset Derivative Fair Value	2,670	4,618	5,037
Carrying Value [Member] | Levels 1 and 2 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale securities	5,578,048	4,393,029	4,118,863
Carrying Value [Member] | Level 3 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-investment, net of allowance for credit losses	5,242,464	5,104,499	5,184,120
Estimated Fair Value [Member] | Level 1 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and due from banks	190,061	211,113	188,373
Interest-bearing demand deposits in banks	654,531	517,971	196,426
Deposits with no stated maturities	9,311,213	8,200,275	7,691,520
Estimated Fair Value [Member] | Level 1 Inputs [Member] | Forward Mortgage-Backed Securities Trades [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Forward mortgage-backed securities trades liability	(376)	(1,560)	(1,099)
Estimated Fair Value [Member] | Level 2 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale	61,969	84,233	66,630
Accrued interest receivable	54,128	53,433	45,801
Deposits with stated maturities	471,857	477,218	468,819
Borrowings	549,969	430,093	449,224
Accrued interest payable	316	377	541
Estimated Fair Value [Member] | Level 2 Inputs [Member] | IRLCs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Asset Derivative Fair Value	2,670	4,618	5,037
Estimated Fair Value [Member] | Levels 1 and 2 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale securities	5,578,048	4,393,029	4,118,863
Estimated Fair Value [Member] | Level 3 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held-for-investment, net of allowance for credit losses	$ 5,273,264	$ 5,109,885	$ 5,174,126

Acquisition - Additional Inform

Acquisition - Additional Information (Detail) - USD ($)	Jan. 02, 2020	Sep. 19, 2019	Jun. 30, 2021
FBC Bancshares, Inc. and First Bank, N.A. [Member]
Business Acquisition [Line Items]
Payment for all outstanding shares of acquired entity by shares		6,275,574
Fair value of total loans			$ 447,702,000
Total loans of contractual amounts			$ 455,181,000
Commercial Bancshares, Inc [Member]
Business Acquisition [Line Items]
Business acquisition, agreement date			Sep. 19, 2019
Payment for all outstanding shares of acquired entity by shares	6,275,574
Business acquisition, special dividend	$ 1,920,000

Acquisition - Schedule of Amoun

Acquisition - Schedule of Amounts Recorded on Consolidated Balance Sheet on Acquisition Date (Detail) $ in Thousands	Sep. 19, 2019USD ($)
FBC Bancshares, Inc. and First Bank, N.A. [Member]
Business Acquisition [Line Items]
Common stock issued (6,275,574 shares)	$ 220,273

Acquisition - Schedule of Amo_2

Acquisition - Schedule of Amounts Recorded on Consolidated Balance Sheet on Acquisition Date (Parenthetical) (Detail)	Sep. 19, 2019shares
FBC Bancshares, Inc. and First Bank, N.A. [Member]
Business Acquisition [Line Items]
Common stock issued	6,275,574

Acquisition - Schedule of Preli

Acquisition - Schedule of Preliminary Estimated Fair Value Amounts Assigned to Major Asset and Liability Categories at Acquisition Date (Detail) - FBC Bancshares, Inc. and First Bank, N.A. [Member] $ in Thousands	Jun. 30, 2021USD ($)
Business Acquisition [Line Items]
Cash and cash equivalents	$ 61,028
Securities available-for-sale	93,967
Loans	447,702
Identifiable intangible assets	4,798
Other assets	25,377
Total identifiable assets acquired	632,872
Deposits	549,125
Other liabilities	5,397
Total liabilities assumed	554,522
Fair value of net identifiable assets acquired	78,350
Goodwill resulting from acquisition	$ 141,923